Merge branch 'maint'

* maint:
  tests: rework tests on AM_PATH_PYTHON
  cosmetics: fix typos and references in comments
  typofix: in a test diagnostic
  readme: fixlets to HACKING

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

208 files changed, 408 insertions, 502 deletions

diff --git a/HACKING b/HACKING
index 696638447..e2450396a 100644
--- a/HACKING
+++ b/HACKING
@@ -1,10 +1,10 @@
-================================================================
+============================================================================
 = This file
 
 * This file attempts to describe the rules to use when hacking
   automake.
 
-================================================================
+============================================================================
 = Administrivia
 
 * The correct response to most actual bugs is to write a new test case
@@ -38,7 +38,7 @@
 * Changes other than bug fixes must be mentioned in NEWS.  Important
   bug fixes should be mentioned in NEWS, too.
 
-================================================================
+============================================================================
 = Naming
 
 * We've adopted the convention that internal AC_SUBSTs should be
@@ -52,7 +52,7 @@
   variable begins with the underscore character.  Yay for them.
   I changed the target naming convention just to be safe.
 
-================================================================
+============================================================================
 = Editing '.am' files
 
 * Always use $(...) and not ${...}
@@ -78,7 +78,7 @@
 * Ensure install rules do not create any installation directory where
   nothing is to be actually installed.  See automake bug#11030.
 
-================================================================
+============================================================================
 = Editing automake.in and aclocal.in
 
 * Indent using GNU style.  For historical reasons, the perl code
@@ -92,7 +92,7 @@
   &, just convert the old code as you work on it, and write new
   code without.
 
-================================================================
+============================================================================
 = Working with git
 
 * To regenerate dependent files created by aclocal and automake,
@@ -136,7 +136,7 @@
   release.  For next, and for feature branches, the announcement for the
   branch should document rewinding policy.
 
-================================================================
+============================================================================
 = Writing a good commit message
 
 * Here is the general format that Automake's commit messages are expected
@@ -197,7 +197,7 @@
       ... removed in commit 'v1.11-1674-g02e9072' of 01-01-2012,
       "dist: ditch support for lzma"...
 
-================================================================
+============================================================================
 = Test suite
 
 * Use "make check" and "make maintainer-check" liberally.
@@ -212,7 +212,7 @@
 
 * See file 't/README' for more information.
 
-================================================================
+============================================================================
 = Release procedure
 
 * The steps outlined here are meant to be followed for alpha and stable
@@ -227,7 +227,8 @@
   date.  The maintainer-only target "update-copyright" can help with
   this.
 
-* Update NEWS.
+* Check NEWS; in particular, ensure that all the relevant differences
+  with the last release are actually reported.
 
 * Update the version number in configure.ac.
   (The idea is that every other alpha number will be a net release.
@@ -235,7 +236,13 @@
   distinguish net and repo versions.)
 
 * Run this:
-  ./bootstrap.sh && ./configure && make && make check && make distcheck
+
+    make bootstrap && make check && make distcheck
+
+  It is also advised to run "git clean -fdx" before invoking the
+  bootstrap, to ensure a really clean rebuild.  However, it must
+  be done carefully, because that command will remove *all* the
+  files that are not tracked by git!
 
 * Run "make git-tag-release".
   This will run the maintainer checks, verify that the local git
diff --git a/doc/automake.texi b/doc/automake.texi
index 76e84e089..e4614ab23 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -8418,7 +8418,7 @@ dist-hook:
         rm -rf `find $(distdir)/doc -type d -name .svn`
 @end example
 
-@c The caveates described here should be documented in 'disthook.test'.
+@c The caveates described here should be documented in 'disthook.sh'.
 @noindent
 Note that the @code{dist-hook} recipe shouldn't assume that the regular
 files in the distribution directory are writable; this might not be the
@@ -9178,7 +9178,7 @@ parallel @command{make -j@var{N}}, so be sure they are prepared for
 concurrent execution.
 
 @cindex Unit tests
-@c Keep in sync with 'parallel-tests-extra-programs.test'.
+@c Keep in sync with 'parallel-tests-extra-programs.sh'.
 The combination of lazy test execution and correct dependencies between
 tests and their sources may be exploited for efficient unit testing
 during development.  To further speed up the edit-compile-test cycle, it
@@ -9436,7 +9436,7 @@ text holding the name and/or a brief description of the corresponding
 test; the harness will ignore such extra text when generating
 @file{test-suite.log} and preparing the testsuite summary.
 
-@c Keep in sync with 'test-metadata-recheck.test'.
+@c Keep in sync with 'test-metadata-recheck.sh'.
 @item @code{:recheck:}
 @cindex :recheck:
 @cindex reStructuredText field, @code{:recheck:}
@@ -9445,7 +9445,7 @@ test script will @emph{not} be run upon a @command{make recheck}.  What
 happens when two or more @code{:recheck:} fields are present in the same
 @file{.trs} file is undefined behaviour.
 
-@c Keep in sync with 'test-metadata-global-log.test'.
+@c Keep in sync with 'test-metadata-global-log.sh'.
 @item @code{:copy-in-global-log:}
 @cindex :copy-in-global-log:
 @cindex reStructuredText field, @code{:copy-in-global-log:}
@@ -9457,7 +9457,7 @@ just a waste of space in normal situations, e.g., when a test script is
 successful.  What happens when two or more @code{:copy-in-global-log:}
 fields are present in the same @file{.trs} file is undefined behaviour.
 
-@c Keep in sync with 'test-metadata-global-result.test'.
+@c Keep in sync with 'test-metadata-global-result.sh'.
 @item @code{:test-global-result:}
 @cindex :test-global-result:
 @cindex reStructuredText field, @code{:test-global-result:}
@@ -9582,7 +9582,7 @@ supports the following options, whose names are chosen for enhanced
 compatibility with the @command{prove} utility.
 
 @table @option
-@c Keep in sync with 'tap-exit.test' and 'tap-signal.tap'.
+@c Keep in sync with 'tap-exit.sh' and 'tap-signal.tap'.
 @item --ignore-exit
 Causes the test driver to ignore the exit status of the test scripts;
 by default, the driver will report an error if the script exits with a
diff --git a/lib/am/check.am b/lib/am/check.am
index c1e8aac24..f085f8e9e 100644
--- a/lib/am/check.am
+++ b/lib/am/check.am
@@ -218,7 +218,7 @@ $(AM_TESTS_ENVIRONMENT) $(TESTS_ENVIRONMENT)
 # '$bases'.  This honors runtime overriding of TESTS and TEST_LOGS.  Sadly,
 # we cannot use something simpler, involving e.g., "$(TEST_LOGS:.log=)",
 # since that might cause problem with VPATH rewrites for suffix-less tests.
-# See also 'test-harness-vpath-rewrite.test' and 'test-trs-basic.test'.
+# See also 'test-harness-vpath-rewrite.sh' and 'test-trs-basic.sh'.
 am__set_TESTS_bases = \
   bases='$(TEST_LOGS)'; \
   bases=`for i in $$bases; do echo $$i; done | sed 's/\.log$$//'`; \
@@ -447,7 +447,7 @@ recheck: all %CHECK_DEPS%
 ##     we must ensure that any '.log' and '.trs' file referring to such
 ##     test are preserved, so that future "make recheck" invocations
 ##     will still try to re-compile and re-run it (automake bug#11791).
-## The tricky recusrive make invocation below should cater to such
+## The tricky recursive make invocation below should cater to such
 ## requirements.
 	$(MAKE) $(AM_MAKEFLAGS) $(TEST_SUITE_LOG) \
 	        am__force_recheck=am--force-recheck \
diff --git a/t/acloca10.sh b/t/acloca10.sh
index ec9a50624..d12035214 100755
--- a/t/acloca10.sh
+++ b/t/acloca10.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure aclocal define macros in the same order as -I's.
-# This is the same as aclocal9.test, with the macro calls reversed.
+# This is the same as aclocal9.sh, with the macro calls reversed.
 # (It did make a difference.)
 #
 # Also check for --install.
diff --git a/t/acloca12.sh b/t/acloca12.sh
index 64b66bb48..01acb0281 100755
--- a/t/acloca12.sh
+++ b/t/acloca12.sh
@@ -16,7 +16,7 @@
 
 # Make sure that when two files define the same macro in the same
 # directory, the macro from the lexically greatest file is used.
-# Same as acloca11.test, but without calling MACRO2.
+# Same as acloca11.sh, but without calling MACRO2.
 
 am_create_testdir=empty
 . ./defs || exit 1
diff --git a/t/acloca22.sh b/t/acloca22.sh
index c23a7cb21..ea76579d9 100755
--- a/t/acloca22.sh
+++ b/t/acloca22.sh
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure the "deleted header file" issue is fixed w.r.t. aclocal.m4
-# dependencies.  See also related the tests 'remake-deleted-m4-file.test'
-# and 'remake-renamed-m4-macro-and-file.test'.
+# dependencies.  See also related the tests 'remake-deleted-m4-file.sh'
+# and 'remake-renamed-m4-macro-and-file.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/aclocal5.sh b/t/aclocal5.sh
index cf0006d0a..a33798699 100755
--- a/t/aclocal5.sh
+++ b/t/aclocal5.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure that aclocal.m4's dependencies are honored in
-# sub-directories.  See also related tests 'remake-subdir*.test'.
+# sub-directories.  See also related tests 'remake-subdir*.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/ar-lib5a.sh b/t/ar-lib5a.sh
index abfe51394..a11e218f7 100755
--- a/t/ar-lib5a.sh
+++ b/t/ar-lib5a.sh
@@ -16,7 +16,7 @@
 
 # Test if AM_PROG_AR triggers the use of the ar-lib script.
 # This test requires Microsoft lib.
-# Keep this test in sync with sister test 'ar-lib5b.test'.
+# Keep this test in sync with sister test 'ar-lib5b.sh'.
 
 required=lib
 . ./defs || exit 1
diff --git a/t/ar-lib5b.sh b/t/ar-lib5b.sh
index 451b337eb..a3007602c 100755
--- a/t/ar-lib5b.sh
+++ b/t/ar-lib5b.sh
@@ -16,7 +16,7 @@
 
 # Test if AM_PROG_AR triggers the use of the ar-lib script.
 # This test does not require Microsoft lib.
-# Keep this test in sync with sister test 'ar-lib5a.test'.
+# Keep this test in sync with sister test 'ar-lib5a.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/ar-lib6a.sh b/t/ar-lib6a.sh
index 4ccaa5dd9..7ee5257c1 100755
--- a/t/ar-lib6a.sh
+++ b/t/ar-lib6a.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test AM_PROG_AR ordering requirements
-# Keep this test in sync with sister test 'ar-lib6b.test'.
+# Keep this test in sync with sister test 'ar-lib6b.sh'.
 
 required=libtoolize
 . ./defs || exit 1
diff --git a/t/ar-lib6b.sh b/t/ar-lib6b.sh
index bebf7152e..92709f851 100755
--- a/t/ar-lib6b.sh
+++ b/t/ar-lib6b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test AM_PROG_AR ordering requirements for older Libtools
-# Keep this test in sync with sister test 'ar-lib6a.test'.
+# Keep this test in sync with sister test 'ar-lib6a.sh'.
 
 required=libtoolize
 . ./defs || exit 1
diff --git a/t/asm.sh b/t/asm.sh
index c2f20b1db..48df68b2c 100755
--- a/t/asm.sh
+++ b/t/asm.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test of basic assembly functionality.
-# Keep this in sync with sister tests asm2.test and asm3.test.
+# Keep this in sync with sister tests 'asm2.sh' and 'asm3.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/asm2.sh b/t/asm2.sh
index 1c50690ac..d62cb60b8 100755
--- a/t/asm2.sh
+++ b/t/asm2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test of basic preprocessed assembly functionality.
-# Keep this in sync with sister tests asm.test and asm3.test.
+# Keep this in sync with sister tests 'asm.sh' and 'asm3.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/asm3.sh b/t/asm3.sh
index e1147644d..67bb876a6 100755
--- a/t/asm3.sh
+++ b/t/asm3.sh
@@ -14,8 +14,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Test of basic preprocessed assembly functionality with extension .sx.
-# Keep this in sync with sister tests asm.test and asm2.test.
+# Test of basic preprocessed assembly functionality with extension '.sx'.
+# Keep this in sync with sister tests 'asm.sh' and 'asm2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/autodist-subdir.sh b/t/autodist-subdir.sh
index 27971ef18..9af7128ac 100755
--- a/t/autodist-subdir.sh
+++ b/t/autodist-subdir.sh
@@ -22,7 +22,7 @@
 # discussion of automake bug#7819:
 #  <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=7819>
 #
-# Keep this test in sync with sister test 'autodist.test'.
+# Keep this test in sync with sister test 'autodist.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/autodist.sh b/t/autodist.sh
index f49985c55..2e591de38 100755
--- a/t/autodist.sh
+++ b/t/autodist.sh
@@ -17,7 +17,7 @@
 # Check that automake really automatically distributes all the files
 # it advertises to do.
 # Related to automake bug#7819.
-# Keep this test in sync with sister test 'autodist-subdir.test'.
+# Keep this test in sync with sister test 'autodist-subdir.sh'.
 
 am_create_testdir=empty
 . ./defs || exit 1
diff --git a/t/auxdir6.sh b/t/auxdir6.sh
index 2194db8ee..b07cd13a3 100755
--- a/t/auxdir6.sh
+++ b/t/auxdir6.sh
@@ -18,7 +18,7 @@
 # This test calls AC_CONFIG_AUX_DIR with an explicit literal argument,
 # thus explicitly making the directory named by that argument the
 # config auxdir.
-# Keep this in sync with sister tests auxdir7.test and auxdir8.test.
+# Keep this in sync with sister tests 'auxdir7.sh' and 'auxdir8.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/auxdir7.sh b/t/auxdir7.sh
index 858a67621..2c82bcbde 100755
--- a/t/auxdir7.sh
+++ b/t/auxdir7.sh
@@ -17,7 +17,7 @@
 # Test to make sure AC_CONFIG_AUX_DIR works correctly.
 # This test calls AC_CONFIG_AUX_DIR with a '.' argument, thus explicitly
 # making the top-level directory the config auxdir.
-# Keep this in sync with sister tests auxdir6.test and auxdir8.test.
+# Keep this in sync with sister tests 'auxdir6.sh' and 'auxdir8.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/auxdir8.sh b/t/auxdir8.sh
index 317c64b94..c4043293c 100755
--- a/t/auxdir8.sh
+++ b/t/auxdir8.sh
@@ -19,7 +19,7 @@
 # the config auxdir should be implicitly defined to '.' since
 # the install-sh, mkinstalldirs, etc., scripts are in the top-level
 # directory.
-# Keep this in sync with sister tests auxdir6.test and auxdir7.test.
+# Keep this in sync with sister tests 'auxdir6.sh' and 'auxdir7.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/canon4.sh b/t/canon4.sh
index e57667d5f..c79b15141 100755
--- a/t/canon4.sh
+++ b/t/canon4.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure name canonicalization happens for static libraries.
-# Keep this in sync with sister test 'canon6.test'.
+# Keep this in sync with sister test 'canon6.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/canon6.sh b/t/canon6.sh
index dc4acd6dc..9c7fd94bf 100755
--- a/t/canon6.sh
+++ b/t/canon6.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure name canonicalization happens for libtool libraries.
-# Keep this in sync with sister test 'canon4.test'.
+# Keep this in sync with sister test 'canon4.sh'.
 
 required='libtoolize'
 . ./defs || exit 1
diff --git a/t/check-fd-redirect.sh b/t/check-fd-redirect.sh
index 0d31e892c..a11d0cdf8 100755
--- a/t/check-fd-redirect.sh
+++ b/t/check-fd-redirect.sh
@@ -16,7 +16,7 @@
 
 # Simple Tests support: redirection of file descriptors with
 # AM_TESTS_FD_REDIRECT.
-# See also related test 'parallel-tests-fd-redirect.test'.
+# See also related test 'parallel-tests-fd-redirect.sh'.
 
 # For gen-testsuite-part: ==> try-with-serial-tests <==
 . ./defs || exit 1
diff --git a/t/check-subst-prog.sh b/t/check-subst-prog.sh
index dc1947ef7..77538cd9e 100755
--- a/t/check-subst-prog.sh
+++ b/t/check-subst-prog.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check @substituted@ TESTS, some of which are also PROGRAMS.
-# See also sister test 'check-subst.test'.
+# See also sister test 'check-subst.sh'.
 
 # For gen-testsuite-part: ==> try-with-serial-tests <==
 required='cc native'
diff --git a/t/check-subst.sh b/t/check-subst.sh
index b743ca335..0b1aedaca 100755
--- a/t/check-subst.sh
+++ b/t/check-subst.sh
@@ -17,7 +17,7 @@
 # Check @substituted@ TESTS.
 # Note that in this test, we rely on the .test extension for the
 # substituted names: this is necessary for the parallel harness.
-# See also sister test 'check-subst-prog.test'.
+# See also sister test 'check-subst-prog.sh'.
 
 # For gen-testsuite-part: ==> try-with-serial-tests <==
 . ./defs || exit 1
diff --git a/t/check.sh b/t/check.sh
index f44c6617d..1717e3b05 100755
--- a/t/check.sh
+++ b/t/check.sh
@@ -35,7 +35,7 @@ grep 'check-DEJAGNU' Makefile.in && exit 1
 sed -n '/^\.PHONY:/,/^$/p' Makefile.in | $EGREP '(^| )check-TESTS($| )'
 
 # 'check' should depend directly on 'check-am' (similar tests are
-# in check2.test and check3.test).
+# in check2.sh and check3.sh).
 $EGREP '^check:.* check-am( |$)' Makefile.in
 
 :
diff --git a/t/check2.sh b/t/check2.sh
index 05dcacb0b..2332fd607 100755
--- a/t/check2.sh
+++ b/t/check2.sh
@@ -57,7 +57,7 @@ grep '^PASS: subrun\.sh *$' stdout
 grep 'PASS.*echo\.sh' stdout && exit 1
 
 # 'check' should depend directly on 'check-am' (similar tests are
-# in check.test and check3.test).
+# in check.sh and check3.sh).
 $EGREP '^check:.* check-recursive( |$)' Makefile.in
 $EGREP '^check:.* check-am( |$)' dir/Makefile.in
 
diff --git a/t/check3.sh b/t/check3.sh
index 64a451266..3e4ce96f8 100755
--- a/t/check3.sh
+++ b/t/check3.sh
@@ -64,7 +64,7 @@ grep '^PASS: subrun\.sh *$' stdout
 grep 'PASS.*echo\.sh' stdout && exit 1
 
 # check should depend directly on $(BUILT_SOURCES) (similar tests
-# are in check.test and check2.test).
+# are in check.sh and check2.sh).
 $EGREP '^check:.* \$\(BUILT_SOURCES\)( |$)' Makefile.in
 $EGREP '^check:.* \$\(BUILT_SOURCES\)( |$)' dir/Makefile.in
 
diff --git a/t/colon2.sh b/t/colon2.sh
index b59ad495f..febf20a29 100755
--- a/t/colon2.sh
+++ b/t/colon2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure ":" works with files automake generates.
-# See also sister test 'colon3.test'.
+# See also sister test 'colon3.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/colon3.sh b/t/colon3.sh
index 5ef22673a..e594d6fb4 100755
--- a/t/colon3.sh
+++ b/t/colon3.sh
@@ -16,7 +16,7 @@
 
 # Make sure ":" works with files automake generates.
 # This test is for multiple ":"s.
-# See also sister test 'colon2.test'.
+# See also sister test 'colon2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/color-tests.sh b/t/color-tests.sh
index fafa40376..8ccfc3fc3 100755
--- a/t/color-tests.sh
+++ b/t/color-tests.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test Automake TESTS color output, by forcing it.
-# Keep this in sync with the sister test 'color2.test'.
+# Keep this in sync with the sister test 'color2.sh'.
 
 required='grep-nonprint'
 # For gen-testsuite-part: ==> try-with-serial-tests <==
diff --git a/t/color-tests2.sh b/t/color-tests2.sh
index 65ca6c72f..d067c9569 100755
--- a/t/color-tests2.sh
+++ b/t/color-tests2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test Automake TESTS color output, using the expect(1) program.
-# Keep this in sync with the sister test 'color.test'.
+# Keep this in sync with the sister test 'color.sh'.
 
 required='grep-nonprint'
 # For gen-testsuite-part: ==> try-with-serial-tests <==
diff --git a/t/compile_f90_c_cxx.sh b/t/compile_f90_c_cxx.sh
index 74a5478b1..27998dc4f 100755
--- a/t/compile_f90_c_cxx.sh
+++ b/t/compile_f90_c_cxx.sh
@@ -16,7 +16,7 @@
 
 # Test to make sure rules to invoke all compilers are selected with
 # mixed source objects.
-# (copied from compile_f_c_cxx.test) Mike Nolta <mrnolta@princeton.edu>
+# (copied from compile_f_c_cxx.sh) Mike Nolta <mrnolta@princeton.edu>
 
 . ./defs || exit 1
 
diff --git a/t/cond44.sh b/t/cond44.sh
index 71c3bcd0d..8d4d7d598 100755
--- a/t/cond44.sh
+++ b/t/cond44.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check that redefinitions of AC_SUBST'ed AM_SUBST_NOTMAKE'd variables
-# are not diagnosed.  See cond23.test.
+# are not diagnosed.  See 'cond23.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/cond45.sh b/t/cond45.sh
index ceddc6365..5e010cf4c 100755
--- a/t/cond45.sh
+++ b/t/cond45.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check that redefinitions of AC_SUBST'ed AM_SUBST_NOTMAKE'd variables
-# are not diagnosed.  See cond24.test.
+# are not diagnosed.  See 'cond24.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/condhook.sh b/t/condhook.sh
index c8675e594..18ebcb343 100755
--- a/t/condhook.sh
+++ b/t/condhook.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test install when a conditional install-*-hook is not defined.
-# Keep this in sync with sister test condhook2.test.
+# Keep this in sync with sister test 'condhook2.sh'.
 # Report by Nik A. Melchior (PR/428).
 
 . ./defs || exit 1
diff --git a/t/condhook2.sh b/t/condhook2.sh
index 1ab8d8852..a6ec7fffb 100755
--- a/t/condhook2.sh
+++ b/t/condhook2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test install when a conditional install-*-hook is defined.
-# Keep this in sync with sister test condhook.test.
+# Keep this in sync with sister test 'condhook.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/confh7.sh b/t/confh7.sh
index ec0edbe9d..dc80ae074 100755
--- a/t/confh7.sh
+++ b/t/confh7.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure several config headers are allowed.
-# See also sister "semantic" test 'confh8.test'.
+# See also sister "semantic" test 'confh8.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/confh8.sh b/t/confh8.sh
index 7379a341d..00013d3e0 100755
--- a/t/confh8.sh
+++ b/t/confh8.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure several config headers are allowed.
-# See also sister "minimalistic" test 'confh7.test'.
+# See also sister "minimalistic" test 'confh7.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/cscope.tap b/t/cscope.tap
index d57b2a8df..9db0d8e81 100755
--- a/t/cscope.tap
+++ b/t/cscope.tap
@@ -156,7 +156,7 @@ if using_gmake; then
 
 else
 
-  skip_row_ 12 -r "cscope in VPATH required GNU make"
+  skip_row_ 12 -r "cscope in VPATH requires GNU make"
 
 fi
 
diff --git a/t/dejagnu.sh b/t/dejagnu.sh
index a3bec5243..7583347bd 100755
--- a/t/dejagnu.sh
+++ b/t/dejagnu.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Superficial test to check that dejagnu tests and automake-style
-# tests can coexist.  See also related deeper test 'check12.test'.
+# tests can coexist.  See also related deeper test 'check12.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/depcomp8a.sh b/t/depcomp8a.sh
index 72e852f9a..4e34777df 100755
--- a/t/depcomp8a.sh
+++ b/t/depcomp8a.sh
@@ -16,7 +16,7 @@
 
 # Test for regressions in computation of names of .Po files for
 # automatic dependency tracking.
-# Keep this in sync with sister test 'depcomp8b.test', which checks the
+# Keep this in sync with sister test 'depcomp8b.sh', which checks the
 # same thing for libtool objects.
 
 required=cc
diff --git a/t/depcomp8b.sh b/t/depcomp8b.sh
index d6399e9ad..3e26392ac 100755
--- a/t/depcomp8b.sh
+++ b/t/depcomp8b.sh
@@ -16,7 +16,7 @@
 
 # Test for regressions in computation of names of .Plo files for
 # automatic dependency tracking.
-# Keep this in sync with sister test 'depcomp8a.test', which checks the
+# Keep this in sync with sister test 'depcomp8a.sh', which checks the
 # same thing for non-libtool objects.
 
 required='cc libtoolize'
diff --git a/t/dist-missing-included-m4.sh b/t/dist-missing-included-m4.sh
index 6a2a57de9..93d11b7de 100755
--- a/t/dist-missing-included-m4.sh
+++ b/t/dist-missing-included-m4.sh
@@ -18,7 +18,7 @@
 # for '.m4' files shouldn't prevent "make" from diagnosing a missing
 # required '.m4' file from a distribution tarball.
 # See discussion about automake bug#9768.
-# See also sister test 'dist-missing-m4.test'.
+# See also sister test 'dist-missing-m4.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/dist-missing-m4.sh b/t/dist-missing-m4.sh
index 4e002e4dd..4ab1e1632 100755
--- a/t/dist-missing-m4.sh
+++ b/t/dist-missing-m4.sh
@@ -18,7 +18,7 @@
 # for '.m4' files shouldn't prevent "make" from diagnosing a missing
 # required '.m4' file from a distribution tarball.
 # See discussion about automake bug#9768.
-# See also sister test 'dist-missing-included-m4.test'.
+# See also sister test 'dist-missing-included-m4.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/distcom-subdir.sh b/t/distcom-subdir.sh
index a841fd9ba..cb4d9c33d 100755
--- a/t/distcom-subdir.sh
+++ b/t/distcom-subdir.sh
@@ -49,7 +49,7 @@ $AUTOMAKE -a subdir/Makefile
 test -f depcomp
 
 # FIXME: the logic of this check and other similar ones in other
-# FIXME: 'distcom*.test' files should be factored out in a common
+# FIXME: 'distcom*.sh' files should be factored out in a common
 # FIXME: subroutine in 'defs'...
 sed -n -e "
   /^DIST_COMMON =.*\\\\$/ {
diff --git a/t/distcom2.sh b/t/distcom2.sh
index 0b218f3d6..27b7dc9a3 100755
--- a/t/distcom2.sh
+++ b/t/distcom2.sh
@@ -51,7 +51,7 @@ for opt in '' --no-force; do
 
   for dir in . subdir; do
     # FIXME: the logic of this check and other similar ones in other
-    # FIXME: 'distcom*.test' files should be factored out in a common
+    # FIXME: 'distcom*.sh' files should be factored out in a common
     # FIXME: subroutine in 'defs'...
     sed -n -e "
       /^DIST_COMMON =.*\\\\$/ {
diff --git a/t/distcom4.sh b/t/distcom4.sh
index c7088eb72..691c19721 100755
--- a/t/distcom4.sh
+++ b/t/distcom4.sh
@@ -16,7 +16,7 @@
 
 # Test to make sure config files are distributed, and only once.
 # This tries to distribute a file from a subdirectory, without
-# Makefile in that directory.  distcom5.test performs the same
+# Makefile in that directory.  'distcom5.sh' performs the same
 # test with a Makefile in the directory.
 
 . ./defs || exit 1
diff --git a/t/distcom5.sh b/t/distcom5.sh
index 0ee2946cc..6a2c7366e 100755
--- a/t/distcom5.sh
+++ b/t/distcom5.sh
@@ -16,7 +16,7 @@
 
 # Test to make sure config files are distributed, and only once.
 # This tries to distribute a file from a subdirectory, with
-# a Makefile in that directory.  distcom4.test performs the same
+# a Makefile in that directory.  'distcom4.sh' performs the same
 # test without Makefile in the directory.
 
 . ./defs || exit 1
diff --git a/t/extra10.sh b/t/extra10.sh
index de8242258..db34e1117 100755
--- a/t/extra10.sh
+++ b/t/extra10.sh
@@ -16,7 +16,7 @@
 
 # Check that wildcards in EXTRA_DIST are honoured.
 # Suggested by observations from Braden McDaniel.
-# See also sister test 'extra11.test', that check a similar usage
+# See also sister test 'extra11.sh', that checks a similar usage
 # with the involvement of the $(wildcard) GNU make builtin.
 
 required=GNUmake
diff --git a/t/extradep2.sh b/t/extradep2.sh
index 554d0be94..eecf74fc2 100755
--- a/t/extradep2.sh
+++ b/t/extradep2.sh
@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Test EXTRA_*_DEPENDENCIES, libtool version; see extradep.test.
+# Test EXTRA_*_DEPENDENCIES, libtool version; see 'extradep.sh'.
 
 required='cc libtoolize'
 . ./defs || exit 1
diff --git a/t/f90only.sh b/t/f90only.sh
index 56e63effa..3d23628e3 100755
--- a/t/f90only.sh
+++ b/t/f90only.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure programs with only Fortran 90 source are handled properly.
-# (copied from fonly.test) Mike Nolta <mrnolta@princeton.edu>
+# (copied from 'fonly.sh') Mike Nolta <mrnolta@princeton.edu>
 
 . ./defs || exit 1
 
diff --git a/t/fort2.sh b/t/fort2.sh
index cb93e7947..fbe05b761 100755
--- a/t/fort2.sh
+++ b/t/fort2.sh
@@ -17,7 +17,7 @@
 # Test that AC_FC_SRCEXT(f9x) works as intended:
 # - $(FCFLAGS_f) will be used
 
-# Cf. fort1.test and link_f90_only.test.
+# Cf. 'fort1.sh' and 'link_f90_only.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/gnits2.sh b/t/gnits2.sh
index bf8ec34b4..337c0ae5e 100755
--- a/t/gnits2.sh
+++ b/t/gnits2.sh
@@ -91,7 +91,7 @@ chmod +x sub/scriptnok.sh
 : > THANKS
 
 # The following file should not be distributed.
-# (alpha.test checks the case where it must be distributed.)
+# (alpha.sh checks the case where it must be distributed.)
 : > README-alpha
 
 $ACLOCAL
diff --git a/t/help-depend.sh b/t/help-depend.sh
index 1c2cb436b..9a27d0b0a 100755
--- a/t/help-depend.sh
+++ b/t/help-depend.sh
@@ -16,7 +16,7 @@
 
 # Make sure that our private macro 'AM_DEP_TRACK' adds proper text to
 # the configure help screen.
-# Keep this in sync with sister test 'help-depend2.test'
+# Keep this in sync with sister test 'help-depend2.sh'
 
 . ./defs || exit 1
 
diff --git a/t/help-depend2.sh b/t/help-depend2.sh
index b40b6f342..5cf1273e2 100755
--- a/t/help-depend2.sh
+++ b/t/help-depend2.sh
@@ -16,7 +16,7 @@
 
 # Make sure that when automake automatically activates support for
 # dependency tracking, it adds proper text to the configure help screen.
-# Keep this in sync with sister test 'help-depend.test'
+# Keep this in sync with sister test 'help-depend.sh'
 
 . ./defs || exit 1
 
diff --git a/t/install-info-dir.sh b/t/install-info-dir.sh
index 39995fc7e..abf16e343 100755
--- a/t/install-info-dir.sh
+++ b/t/install-info-dir.sh
@@ -19,7 +19,7 @@
 # inlined, below.
 
 # FIXME: this test is a good candidate for a conversion to TAP,
-# FIXME: and could be merged with 'txinfo27.test'.
+# FIXME: and could be merged with 'txinfo27.sh'.
 
 required=makeinfo
 . ./defs || exit 1
diff --git a/t/instdir-cond2.sh b/t/instdir-cond2.sh
index 8f386cc34..559a7fe85 100755
--- a/t/instdir-cond2.sh
+++ b/t/instdir-cond2.sh
@@ -19,7 +19,7 @@
 # FIXME: this test tries to check that the above also hold for the
 # FIXME: "installdirs" target, but that doesn't currently work :-(
 # FIXME: So this test is still xfailing.
-# See sister test 'instdir-cond.test' for the succeeding part.
+# See sister test 'instdir-cond.sh' for the succeeding part.
 
 . ./defs || exit 1
 
diff --git a/t/instdir.sh b/t/instdir.sh
index d0c253271..6c489fba5 100755
--- a/t/instdir.sh
+++ b/t/instdir.sh
@@ -16,7 +16,7 @@
 
 # If $(foodir) is the empty string, then nothing should be installed there.
 # This test only ensures this if $(foo_PRIMARY) is also empty, see
-# instdir2.test and siblings instdir-*.test for nonempty contents.
+# 'instdir2.sh' and siblings 'instdir-*.sh' for nonempty contents.
 
 . ./defs || exit 1
 
diff --git a/t/instdir2.sh b/t/instdir2.sh
index 51e78bedc..638e25a2b 100755
--- a/t/instdir2.sh
+++ b/t/instdir2.sh
@@ -16,7 +16,7 @@
 
 # If $(foodir) is the empty string, then nothing should be installed there.
 # This test ensures this also if $(foo_PRIMARY) is nonempty, see
-# instdir.test.
+# 'instdir.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/instfail-info.sh b/t/instfail-info.sh
index ee994dffe..fea2f5b34 100755
--- a/t/instfail-info.sh
+++ b/t/instfail-info.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # The install rule should honor failures of the install program.
-# Some of these are already caught by instmany.test.
+# Some of these are already caught by 'instmany.sh'.
 
 # This test has a few sister tests, for java, info, libtool.
 
diff --git a/t/instfail-java.sh b/t/instfail-java.sh
index 18525a426..7211efa6e 100755
--- a/t/instfail-java.sh
+++ b/t/instfail-java.sh
@@ -15,9 +15,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # The install rule should honor failures of the install program.
-# Some of these are already caught by instmany.test.
+# Some of these are already caught by 'instmany.sh'.
 
-# This is the java sister test of instfail.test.
+# This is the java sister test of 'instfail.sh'.
 
 required=javac
 . ./defs || exit 1
diff --git a/t/instfail-libtool.sh b/t/instfail-libtool.sh
index 2b3bf2f60..042f07782 100755
--- a/t/instfail-libtool.sh
+++ b/t/instfail-libtool.sh
@@ -15,9 +15,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # The install rule should honor failures of the install program.
-# Some of these are already caught by instmany.test.
+# Some of these are already caught by 'instmany.sh'.
 
-# This is the libtool sister test of instfail.test
+# This is the libtool sister test of 'instfail.sh'.
 
 required='cc libtool libtoolize'
 . ./defs || exit 1
diff --git a/t/instfail.sh b/t/instfail.sh
index 5f29c83e8..123e08286 100755
--- a/t/instfail.sh
+++ b/t/instfail.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # The install rule should honor failures of the install program.
-# Some of these are already caught by instmany.test.
+# Some of these are already caught by 'instmany.sh'.
 
 # This test has a few sister tests, for java, info, libtool.
 
diff --git a/t/instmany-mans.sh b/t/instmany-mans.sh
index 68d1ba73f..4fd703b5e 100755
--- a/t/instmany-mans.sh
+++ b/t/instmany-mans.sh
@@ -16,7 +16,7 @@
 
 # Installing many files should not exceed the command line length limit.
 
-# This is the mans sister test of instmany.test, see there for details.
+# This is the mans sister test of 'instmany.sh', see there for details.
 
 . ./defs || exit 1
 
diff --git a/t/instmany-python.sh b/t/instmany-python.sh
index 5cf128cb0..9cc659ad5 100755
--- a/t/instmany-python.sh
+++ b/t/instmany-python.sh
@@ -16,7 +16,7 @@
 
 # Installing many files should not exceed the command line length limit.
 
-# This is the python sister test of instmany.test, see there for details.
+# This is the python sister test of 'instmany.sh', see there for details.
 
 required='python'
 . ./defs || exit 1
diff --git a/t/java-compile-run-flat.sh b/t/java-compile-run-flat.sh
index 05cf89ab2..7d228bb1f 100755
--- a/t/java-compile-run-flat.sh
+++ b/t/java-compile-run-flat.sh
@@ -19,7 +19,7 @@
 # "UNIX-style" use case.
 # This test uses a "flat" setup for the source tree (i.e., everything in
 # the top-level directory), and forces the use of the old, non-parallel
-# testsuite driver.  The sister test 'java-compile-run-nested.test' do
+# testsuite driver.  The sister test 'java-compile-run-nested.sh' do
 # similar checks with a more usual, "nested" setup, and using the older
 # 'serial-tests' driver.
 
diff --git a/t/java-compile-run-nested.sh b/t/java-compile-run-nested.sh
index f6bb2173f..9c0958cdd 100755
--- a/t/java-compile-run-nested.sh
+++ b/t/java-compile-run-nested.sh
@@ -20,9 +20,9 @@
 # This test uses a typical "nested" source tree setup (i.e., different
 # components/aspects are separated into different subdirectories), and
 # uses the parallel testsuite driver.
-# The sister test 'java-compile-run-flat.test' do similar checks with a
-# "flat" setup (i.e., everything in the top-level directory), and forcing
-# the use of the older 'serial-tests' driver.
+# The sister test 'java-compile-run-flat.sh' do similar checks with
+# a "flat" setup (i.e., everything in the top-level directory), and
+# forcing the use of the older 'serial-tests' driver.
 
 required='java javac'
 . ./defs || exit 1
diff --git a/t/lex-clean-cxx.sh b/t/lex-clean-cxx.sh
index a61dd98b5..38a129c5a 100755
--- a/t/lex-clean-cxx.sh
+++ b/t/lex-clean-cxx.sh
@@ -17,7 +17,7 @@
 # Check that C++ source files derived from non-distributed Lex sources
 # are cleaned by "make clean", while C++ source files derived from
 # distributed Lex sources are cleaned by "make maintainer-clean".
-# See also sister test 'lex-clean.test'.
+# See also sister test 'lex-clean.sh'.
 
 required='c++ lex'
 . ./defs || exit 1
diff --git a/t/lex-clean.sh b/t/lex-clean.sh
index 91742bf76..3bc52d3aa 100755
--- a/t/lex-clean.sh
+++ b/t/lex-clean.sh
@@ -17,7 +17,7 @@
 # Check that .c files derived from non-distributed .l sources
 # are cleaned by "make clean", while .c files derived from
 # distributed .l sources are cleaned by "make maintainer-clean".
-# See also sister test 'lex-clean-cxx.test'.
+# See also sister test 'lex-clean-cxx.sh'.
 
 required='cc lex'
 . ./defs || exit 1
diff --git a/t/lex-depend-grep.sh b/t/lex-depend-grep.sh
index 4011b8041..e7c953885 100755
--- a/t/lex-depend-grep.sh
+++ b/t/lex-depend-grep.sh
@@ -16,7 +16,7 @@
 
 # Test to make sure dependencies for Lex and C/C++ does not break
 # in obvious ways.  See PR automake/6, and related semantic tests
-# 'lex-depend.test' and 'lex-depend-cxx.test'.
+# 'lex-depend.sh' and 'lex-depend-cxx.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/lex-lib.sh b/t/lex-lib.sh
index 29e2ed84a..11767d890 100755
--- a/t/lex-lib.sh
+++ b/t/lex-lib.sh
@@ -16,7 +16,7 @@
 
 # Check that we can provide a personal 'yywrap' function in a custom
 # library.
-# See also test 'lex-lib-external.test'.
+# See also test 'lex-lib-external.sh'.
 
 required='cc lex'
 . ./defs || exit 1
diff --git a/t/lex-line.sh b/t/lex-line.sh
index 9629cce24..11f40b8e8 100755
--- a/t/lex-line.sh
+++ b/t/lex-line.sh
@@ -17,7 +17,7 @@
 # Check that automake lex support ensures that lex-generated C
 # files use correct "#line" directives.  Try also with the
 # 'subdir-object' option enabled.
-# See also sister test 'yacc-line.test'.
+# See also sister test 'yacc-line.sh'.
 
 required='cc lex'
 . ./defs || exit 1
diff --git a/t/lex-nodist.sh b/t/lex-nodist.sh
index b2f7b2944..0bbb6cbe4 100755
--- a/t/lex-nodist.sh
+++ b/t/lex-nodist.sh
@@ -15,9 +15,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Checks for .c files derived from non-distributed .l sources.
-# The test 'lex-pr204.test' does similar check with AM_MAINTAINER_MODE
+# The test 'lex-pr204.sh' does similar check with AM_MAINTAINER_MODE
 # enabled.
-# The tests 'yacc-nodist.test' and 'yacc-pr204.test' does similar checks
+# The tests 'yacc-nodist.sh' and 'yacc-pr204.sh' does similar checks
 # for yacc-generated .c and .h files.
 
 required='cc lex'
@@ -25,7 +25,7 @@ required='cc lex'
 
 cat >> configure.ac << 'END'
 AC_PROG_CC
-dnl Sister test 'lex-pr204.test' should use 'AC_PROG_LEX' instead.
+dnl Sister test 'lex-pr204.sh' should use 'AC_PROG_LEX' instead.
 AM_PROG_LEX
 AC_OUTPUT
 END
diff --git a/t/lex-pr204.sh b/t/lex-pr204.sh
index 535b482ca..8172ec7f1 100755
--- a/t/lex-pr204.sh
+++ b/t/lex-pr204.sh
@@ -16,8 +16,8 @@
 
 # Related to PR 204.
 # C sources derived from nodist_ lex sources should not be distributed.
-# See also related test 'lex-nodist.test'.
-# The tests 'yacc-nodist.test' and 'yacc-pr204.test' does similar checks
+# See also related test 'lex-nodist.sh'.
+# The tests 'yacc-nodist.sh' and 'yacc-pr204.sh' does similar checks
 # for yacc-generated .c and .h files.
 
 required='cc lex'
@@ -27,7 +27,7 @@ cat >> configure.ac <<'EOF'
 AM_MAINTAINER_MODE
 AC_PROG_CC
 dnl We use AC_PROG_LEX deliberately.
-dnl Sister 'lex-nodist.test' should use 'AM_PROG_LEX' instead.
+dnl Sister 'lex-nodist.sh' should use 'AM_PROG_LEX' instead.
 AC_PROG_LEX
 AC_OUTPUT
 EOF
diff --git a/t/lexcpp.sh b/t/lexcpp.sh
index 683f7ea57..d46c82d34 100755
--- a/t/lexcpp.sh
+++ b/t/lexcpp.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure Lex + C++ is supported.
-# Please keep this is sync with sister test yaccpp.test.
+# Please keep this is sync with sister test 'yaccpp.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/lexvpath.sh b/t/lexvpath.sh
index 2c13c96fc..569048ebe 100755
--- a/t/lexvpath.sh
+++ b/t/lexvpath.sh
@@ -20,7 +20,7 @@
 # 'make' and 'make distdir' and check whether the version of 'lexer.c'
 # to be distributed is up to date.
 
-# Please keep this in sync with sister test 'yaccvapth.test'.
+# Please keep this in sync with sister test 'yaccvapth.sh'.
 
 required='cc lex'
 . ./defs || exit 1
diff --git a/t/lflags.sh b/t/lflags.sh
index 22fbbd616..933f89698 100755
--- a/t/lflags.sh
+++ b/t/lflags.sh
@@ -16,8 +16,8 @@
 
 # Check that $(LFLAGS) takes precedence over both $(AM_LFLAGS) and
 # $(foo_LFLAGS).
-# Please keep this in sync with the sister tests lflags2.test, yflags.test
-# and yflags2.test.
+# Please keep this in sync with the sister tests lflags2.sh, yflags.sh
+# and yflags2.sh.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/lflags2.sh b/t/lflags2.sh
index ec398037b..f657da550 100755
--- a/t/lflags2.sh
+++ b/t/lflags2.sh
@@ -16,8 +16,8 @@
 
 # Check that $(LFLAGS) takes precedence over both $(AM_LFLAGS) and
 # $(foo_LFLAGS).
-# Please keep this in sync with the sister tests lflags.test, yflags.test
-# and yflags2.test.
+# Please keep this in sync with the sister tests lflags.sh, yflags.sh
+# and yflags2.sh.
 
 . ./defs || exit 1
 
diff --git a/t/libobj12.sh b/t/libobj12.sh
index 4c2b74d87..6c917e29e 100755
--- a/t/libobj12.sh
+++ b/t/libobj12.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test if a file can be mentioned in LIBOBJS and explicitly.
-# (See libobj13.test for the LTLIBRARIES check.)
+# (See libobj13.sh for the LTLIBRARIES check.)
 
 . ./defs || exit 1
 
diff --git a/t/libobj13.sh b/t/libobj13.sh
index 360ff5d2b..3a9ee713a 100755
--- a/t/libobj13.sh
+++ b/t/libobj13.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test if a file can be mentioned in LTLIBOBJS and explicitly.
-# (Like libobj12.test, but for Libtool libraries.)
+# (Like libobj12.sh, but for Libtool libraries.)
 
 required='libtoolize'
 . ./defs || exit 1
diff --git a/t/libobj16a.sh b/t/libobj16a.sh
index 9826446c7..9bf602a61 100755
--- a/t/libobj16a.sh
+++ b/t/libobj16a.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure AC_LIBOBJ and friends work.
-# Please keep this in sync with sister test 'libobj16b.test'.
+# Please keep this in sync with sister test 'libobj16b.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/libobj16b.sh b/t/libobj16b.sh
index 1b8da0836..600572523 100755
--- a/t/libobj16b.sh
+++ b/t/libobj16b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure AC_LIBOBJ and friends work.
-# Please keep this in sync with sister test 'libobj16a.test'.
+# Please keep this in sync with sister test 'libobj16a.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/libobj20a.sh b/t/libobj20a.sh
index 4ff807f72..52c41ecf9 100755
--- a/t/libobj20a.sh
+++ b/t/libobj20a.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test error reporting for AC_CONFIG_LIBOBJ_DIR.
-# See also sister tests 'libobj20b.test' and 'libobj20c.test' .
+# See also sister tests 'libobj20b.sh' and 'libobj20c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/libobj20b.sh b/t/libobj20b.sh
index a90df20b6..d9ba8dad1 100755
--- a/t/libobj20b.sh
+++ b/t/libobj20b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test error reporting for AC_CONFIG_LIBOBJ_DIR.
-# See also sister tests 'libobj20a.test' and 'libobj20c.test' .
+# See also sister tests 'libobj20a.sh' and 'libobj20c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/libobj20c.sh b/t/libobj20c.sh
index 2d1d65b5a..fe6ae6392 100755
--- a/t/libobj20c.sh
+++ b/t/libobj20c.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test error reporting for AC_CONFIG_LIBOBJ_DIR.
-# See also sister tests 'libobj20a.test' and 'libobj20b.test' .
+# See also sister tests 'libobj20a.sh' and 'libobj20b.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/libtool3.sh b/t/libtool3.sh
index 22c72d1d8..fdbd86d42 100755
--- a/t/libtool3.sh
+++ b/t/libtool3.sh
@@ -66,7 +66,7 @@ a (void)
 END
 
 # Use --copy to workaround a bug in Cygwin's 'cp -p' during distcheck.
-# (This bug is already exhibited by subobj9.test.)  In brief: Cygwin's
+# (This bug is already exhibited by subobj9.sh.)  In brief: Cygwin's
 # 'cp -p' tries to preserve group and owner of the source and fails
 # to do so under normal accounts.  With --copy we ensure we own all files.
 
diff --git a/t/libtool9.sh b/t/libtool9.sh
index eb777d807..1bb85ccb2 100755
--- a/t/libtool9.sh
+++ b/t/libtool9.sh
@@ -16,7 +16,7 @@
 
 # Make sure xxx_LINK is defined for each target that requires specific
 # flags.
-# Quite similar to libtool7.test, using AM_LDFLAGS in addition to
+# Quite similar to 'libtool7.sh', using AM_LDFLAGS in addition to
 # xxx_LDFLAGS.
 
 required='cc libtoolize'
diff --git a/t/link_f90_only.sh b/t/link_f90_only.sh
index 252d46a3a..f9c7c18cf 100755
--- a/t/link_f90_only.sh
+++ b/t/link_f90_only.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure the Fortran 90 linker is used when appropriate.
-# (copied from link_f_only.test) Mike Nolta <mrnolta@princeton.edu>
+# (copied from 'link_f_only.sh') Mike Nolta <mrnolta@princeton.edu>
 
 . ./defs || exit 1
 
diff --git a/t/lisp5.sh b/t/lisp5.sh
index c154e3c25..28d7a6284 100755
--- a/t/lisp5.sh
+++ b/t/lisp5.sh
@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Same as lisp4.test, but using the now-recommended way to install
+# Same as 'lisp4.sh', but using the now-recommended way to install
 # non-bytecompiled *.el files.
 
 required=emacs
diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index b3b0b0c23..a29926227 100644
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -874,16 +874,12 @@ t/py-compile-usage.sh \
 t/python.sh \
 t/python2.sh \
 t/python3.sh \
-t/python4.sh \
-t/python5.sh \
-t/python5b.sh \
-t/python6.sh \
-t/python7.sh \
-t/python8.sh \
-t/python9.sh \
 t/python10.sh \
 t/python11.sh \
 t/python12.sh \
+t/python-am-path-iftrue.sh \
+t/python-missing.sh \
+t/python-too-old.sh \
 t/python-dist.sh \
 t/python-vars.sh \
 t/python-virtualenv.sh \
diff --git a/t/maintclean-vpath.sh b/t/maintclean-vpath.sh
index 77f62670f..b5c6ffe49 100755
--- a/t/maintclean-vpath.sh
+++ b/t/maintclean-vpath.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure distclean and maintainer-clean erase the right files.
-# This test is for VPATH builds; see sister test 'maintclean.test'
+# This test is for VPATH builds; see sister test 'maintclean.sh'
 # for in-tree builds.
 
 . ./defs || exit 1
diff --git a/t/maintclean.sh b/t/maintclean.sh
index a2c0e6b75..757cf859e 100755
--- a/t/maintclean.sh
+++ b/t/maintclean.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure distclean and maintainer-clean erase the right files.
-# This test is for in-tree builds; see sister test 'maintclean-vpath.test'
+# This test is for in-tree builds; see sister test 'maintclean-vpath.sh'
 # for VPATH builds.
 
 . ./defs || exit 1
diff --git a/t/nobase-libtool.sh b/t/nobase-libtool.sh
index 2a6bc2a9e..4a6660176 100755
--- a/t/nobase-libtool.sh
+++ b/t/nobase-libtool.sh
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure nobase_* works for libtool libraries and programs as well.
-# This is just the libtool equivalent of nobase.test, split
-# up for greater exposure of nobase.test.
+# This is just the libtool equivalent of 'nobase.sh', split up to allow
+# greater exposure of that test.
 
 required='cc libtoolize'
 . ./defs || exit 1
diff --git a/t/output10.sh b/t/output10.sh
index f0060fdac..c6130f910 100755
--- a/t/output10.sh
+++ b/t/output10.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure an AC_CONFIG_FILES can have an AC_CONFIG_FILES output as input.
-# This is comparable to output9.test, but testing Makefile rules.
+# This is comparable to 'output9.sh', but testing Makefile rules.
 # PR/411
 
 . ./defs || exit 1
diff --git a/t/parallel-tests-dry-run-1.sh b/t/parallel-tests-dry-run-1.sh
index 382ae206b..96764c31e 100755
--- a/t/parallel-tests-dry-run-1.sh
+++ b/t/parallel-tests-dry-run-1.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check interactions between the parallel test harness and "make -n".
-# See also sister test 'parallel-tests-dry-run-2.test'.
+# See also sister test 'parallel-tests-dry-run-2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/parallel-tests-dry-run-2.sh b/t/parallel-tests-dry-run-2.sh
index 11a0f459a..0d324d8ed 100755
--- a/t/parallel-tests-dry-run-2.sh
+++ b/t/parallel-tests-dry-run-2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check interactions between the parallel test harness and "make -n".
-# See also sister test 'parallel-tests-dry-run-1.test'.
+# See also sister test 'parallel-tests-dry-run-1.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/parallel-tests-fd-redirect-exeext.sh b/t/parallel-tests-fd-redirect-exeext.sh
index dd5df9b07..357576524 100755
--- a/t/parallel-tests-fd-redirect-exeext.sh
+++ b/t/parallel-tests-fd-redirect-exeext.sh
@@ -18,8 +18,8 @@
 # AM_TESTS_FD_REDIRECT, for tests which are binary executables
 # We use some tricks to ensure that all code paths in 'lib/am/check2.am'
 # are covered, even on platforms where $(EXEEXT) would be naturally empty.
-# See also the more generic test 'check-fd-redirect.test', and
-# sister test 'parallel-tests-fd-redirect.test'.
+# See also the more generic test 'check-fd-redirect.sh', and
+# sister test 'parallel-tests-fd-redirect.sh'.
 
 required='cc native'
 . ./defs || exit 1
diff --git a/t/parallel-tests-fd-redirect.sh b/t/parallel-tests-fd-redirect.sh
index aaa0d9872..7cb59c350 100755
--- a/t/parallel-tests-fd-redirect.sh
+++ b/t/parallel-tests-fd-redirect.sh
@@ -16,9 +16,9 @@
 
 # parallel-tests support: redirection of file descriptors with
 # AM_TESTS_FD_REDIRECT, even when using tests without suffix.
-# The sister 'parallel-tests-fd-redirect-exeext.test' do a similar
+# The sister 'parallel-tests-fd-redirect-exeext.sh' do a similar
 # check for tests that are binary executables.
-# See also the more generic test 'check-fd-redirect.test'.
+# See also the more generic test 'check-fd-redirect.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/parallel-tests-log-compiler-1.sh b/t/parallel-tests-log-compiler-1.sh
index 9c4ffce00..0e8c9d892 100755
--- a/t/parallel-tests-log-compiler-1.sh
+++ b/t/parallel-tests-log-compiler-1.sh
@@ -17,7 +17,7 @@
 # Check parallel-tests features:
 # - per-extension "test runners" a.k.a. "log compilers" (xxx_LOG_COMPILER
 #   and xxx_LOG_FLAGS), also with AC_SUBST'd stuff.
-# See also related test 'parallel-tests-log-compiler-2.test'.
+# See also related test 'parallel-tests-log-compiler-2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/parallel-tests-log-compiler-2.sh b/t/parallel-tests-log-compiler-2.sh
index 08e2c9d3d..775a4d1bd 100755
--- a/t/parallel-tests-log-compiler-2.sh
+++ b/t/parallel-tests-log-compiler-2.sh
@@ -17,7 +17,7 @@
 # Check parallel-tests features:
 # - per-extension "test runners" a.k.a. "log compilers" (xxx_LOG_COMPILER
 #   and xxx_LOG_FLAGS), when some tests are PROGRAMS.
-# See also related test 'parallel-tests-log-compiler-1.test'.
+# See also related test 'parallel-tests-log-compiler-1.sh'.
 
 required='cc native'
 . ./defs || exit 1
diff --git a/t/parallel-tests-suffix-prog.sh b/t/parallel-tests-suffix-prog.sh
index 4dda0dfda..a0287da34 100755
--- a/t/parallel-tests-suffix-prog.sh
+++ b/t/parallel-tests-suffix-prog.sh
@@ -16,7 +16,7 @@
 
 # Check parallel-tests features:
 # - suffix rules, with PROGRAMS involved
-# See also sister test 'parallel-tests-suffix.test'.
+# See also sister test 'parallel-tests-suffix.sh'.
 
 required='cc native'
 . ./defs || exit 1
diff --git a/t/parallel-tests-suffix.sh b/t/parallel-tests-suffix.sh
index b5931b86c..93c7ea011 100755
--- a/t/parallel-tests-suffix.sh
+++ b/t/parallel-tests-suffix.sh
@@ -16,7 +16,7 @@
 
 # Check parallel-tests features:
 # - suffix rules
-# See also sister test 'parallel-tests-suffix-prog.test'.
+# See also sister test 'parallel-tests-suffix-prog.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/parallel-tests6.sh b/t/parallel-tests6.sh
index 4f46cebe6..b0fc34a00 100755
--- a/t/parallel-tests6.sh
+++ b/t/parallel-tests6.sh
@@ -17,7 +17,7 @@
 # Check parallel-tests features:
 # - empty TESTS
 # BSD make will expand '$(TESTS:=.log)' to '.log' unless overridden.
-# See parallel-tests10.test for a similar issue.
+# See 'parallel-tests10.sh' for a similar issue.
 
 . ./defs || exit 1
 cat >> configure.ac << 'END'
diff --git a/t/pluseq11.sh b/t/pluseq11.sh
index 5ee5d4f64..67dfd3386 100755
--- a/t/pluseq11.sh
+++ b/t/pluseq11.sh
@@ -16,7 +16,7 @@
 
 # Check for bug in variable concatenation with '+=': an extra backslash
 # is erroneously retained in the final value.
-# See also sister test pluseq11b.test.
+# See also sister test 'pluseq11b.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/posixsubst-libraries.sh b/t/posixsubst-libraries.sh
index 4b6b1d613..884e8aa73 100755
--- a/t/posixsubst-libraries.sh
+++ b/t/posixsubst-libraries.sh
@@ -16,7 +16,7 @@
 
 # Test that POSIX variable expansion '$(var:str=rpl)' works when used
 # with the LIBRARIES primary in a "simple" way.
-# Keep this in sync with sister test 'posixsubst-ltlibraries.test'.
+# Keep this in sync with sister test 'posixsubst-ltlibraries.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/posixsubst-ltlibraries.sh b/t/posixsubst-ltlibraries.sh
index fdf858e07..3111954d6 100755
--- a/t/posixsubst-ltlibraries.sh
+++ b/t/posixsubst-ltlibraries.sh
@@ -16,7 +16,7 @@
 
 # Test that POSIX variable expansion '$(var:str=rpl)' works when used
 # with the LTLIBRARIES primary in a "simple" way.
-# Keep this in sync with sister test 'posixsubst-libraries.test'.
+# Keep this in sync with sister test 'posixsubst-libraries.sh'.
 
 required='cc libtool libtoolize'
 . ./defs || exit 1
diff --git a/t/pr279-2.sh b/t/pr279-2.sh
index 2d5221bc6..fbd06ac9c 100755
--- a/t/pr279-2.sh
+++ b/t/pr279-2.sh
@@ -16,7 +16,7 @@
 
 # Another test related to PR 279.
 # Multiple DEPENDENCIES on conditionals.
-# Please keep this in sync with sister test pr279.test.
+# Please keep this in sync with sister test 'pr279.sh'.
 #
 # == Report ==
 # When defining xxx_LDADD and xxx_DEPENDENCIES variables where the
diff --git a/t/pr279.sh b/t/pr279.sh
index f3bc52fce..7f5f7b5b2 100755
--- a/t/pr279.sh
+++ b/t/pr279.sh
@@ -16,7 +16,7 @@
 
 # Test for PR 279.
 # Multiple DEPENDENCIES on conditionals.
-# Please keep this in sync with sister test pr279-2.test.
+# Please keep this in sync with sister test 'pr279-2.sh'.
 #
 # == Report ==
 # When defining xxx_LDADD and xxx_DEPENDENCIES variables where the
diff --git a/t/pr401.sh b/t/pr401.sh
index b1044760f..73a7e2560 100755
--- a/t/pr401.sh
+++ b/t/pr401.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check support for AC_CONFIG_LIBOBJ_DIR vs LIBOBJS.
-# (pr401b.test and pr401c.test do the same for LTLIBOBJS and ALLOCA)
+# (pr401b.sh and pr401c.sh do the same for LTLIBOBJS and ALLOCA)
 
 required=cc
 . ./defs || exit 1
diff --git a/t/pr401b.sh b/t/pr401b.sh
index 5d0adc08f..e5914731d 100755
--- a/t/pr401b.sh
+++ b/t/pr401b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check support for AC_CONFIG_LIBOBJ_DIR vs LTLIBOBJS.
-# (pr401.test and pr401c.test do the same for LIBOBJS and ALLOCA)
+# (pr401.sh and pr401c.sh do the same for LIBOBJS and ALLOCA)
 
 required='cc libtoolize'
 . ./defs || exit 1
diff --git a/t/pr401c.sh b/t/pr401c.sh
index 3336f13a6..e452ab6f9 100755
--- a/t/pr401c.sh
+++ b/t/pr401c.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check support for AC_CONFIG_LIBOBJ_DIR vs ALLOCA.
-# (pr401.test and pr401b.test do the same for LIBOBJS and LTLIBOBJS)
+# (pr401.sh and pr401b.sh do the same for LIBOBJS and LTLIBOBJS)
 
 required=cc
 . ./defs || exit 1
diff --git a/t/primary-prefix-couples-force-valid.sh b/t/primary-prefix-couples-force-valid.sh
index ac539a1e7..a6d7ace47 100755
--- a/t/primary-prefix-couples-force-valid.sh
+++ b/t/primary-prefix-couples-force-valid.sh
@@ -54,7 +54,7 @@ test:
 	test -f '$(bindir)/libquux.a'
 	ls -l '$(libexecdir)/bar.h'
 	test -f '$(libexecdir)/bar.h'
-## If this test is run as root, "test -x" could suceed also for
+## If this test is run as root, "test -x" could succeed also for
 ## non-executable files, so we need to protect the next check.
 ## See automake bug#12041.
 	if test -x Makefile; then echo SKIP THIS; else \
diff --git a/t/primary-prefix-valid-couples.sh b/t/primary-prefix-valid-couples.sh
index 1890369ac..d8cbc30a2 100755
--- a/t/primary-prefix-valid-couples.sh
+++ b/t/primary-prefix-valid-couples.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test for valid prefix/primary combinations.
-# See also test 'primary-prefix-invalid-couples.test'.
+# See also test 'primary-prefix-invalid-couples.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/py-compile-basic.sh b/t/py-compile-basic.sh
index 9e554e25d..73597c35c 100755
--- a/t/py-compile-basic.sh
+++ b/t/py-compile-basic.sh
@@ -16,7 +16,7 @@
 
 # Test more basic functionalities of the 'py-compile' script,
 # with "believable" python sources.  See also related test
-# 'py-compile-basic2.test'.
+# 'py-compile-basic2.sh'.
 
 required=python
 . ./defs || exit 1
diff --git a/t/py-compile-basic2.sh b/t/py-compile-basic2.sh
index c4c7ce0ee..19fdf7257 100755
--- a/t/py-compile-basic2.sh
+++ b/t/py-compile-basic2.sh
@@ -16,7 +16,7 @@
 
 # Test more basic functionalities of the 'py-compile' script, with
 # dummy python sources, but more complex directory layouts.  See also
-# related test 'py-compile-basic.test'.
+# related test 'py-compile-basic.sh'.
 
 required=python
 . ./defs || exit 1
diff --git a/t/python9.sh b/t/python-am-path-iftrue.sh
index 41f32e58d..3c5201fe8 100755..100644
--- a/t/python9.sh
+++ b/t/python-am-path-iftrue.sh
@@ -15,23 +15,38 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test ACTION-IF-TRUE in AM_PATH_PYTHON.
-# Similar to python8.test, but requiring a version.
 
+am_create_testdir=empty
 required=python
 . ./defs || exit 1
 
-cat >>configure.ac <<'EOF'
-# $PYTHON is supposed to be properly set in ACTION-IF-TRUE.
-AM_PATH_PYTHON([0.0], [$PYTHON -c 'print("%u:%u" % (1-1, 2**0))' > py.out])
+cat > configure.ac <<END
+AC_INIT([$me], [1.0])
+m4_include([mypy.m4])
 AC_OUTPUT
-EOF
+END
 
-: > Makefile.am
+# $PYTHON is supposed to be properly set in ACTION-IF-TRUE.
+cat > mypy.m4 << 'END'
+AM_PATH_PYTHON(, [$PYTHON -V >py-version 2>&1])
+END
 
 $ACLOCAL
 $AUTOCONF
-$AUTOMAKE --add-missing
+./configure
+grep '^Python [0-9]\.[0-9][0-9]*\.[0-9]' py-version
+
+# The same, but requiring a version.
+
+rm -rf autom4te*.cache
 
+# $PYTHON is supposed to be properly set in ACTION-IF-TRUE.
+cat > mypy.m4 << 'END'
+AM_PATH_PYTHON([0.0], [$PYTHON -c 'print("%u:%u" % (1-1, 2**0))' > py.out])
+END
+
+$ACLOCAL
+$AUTOCONF
 ./configure
 test x"$(cat py.out)" = x0:1
 
diff --git a/t/python-missing.sh b/t/python-missing.sh
new file mode 100644
index 000000000..c88a4f972
--- /dev/null
+++ b/t/python-missing.sh
@@ -0,0 +1,80 @@
+#! /bin/sh
+# Copyright (C) 2003-2012 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Test detection of missing Python.
+# See also related test t/python-am-path-missing-2.sh (which requires
+# an actual python program).
+
+am_create_testdir=empty
+# An actual python is *not* required in this test.
+. ./defs || exit 1
+
+PYTHON=; unset PYTHON
+
+cat > configure.ac <<END
+AC_INIT([$me], [1.0])
+m4_include([mypy.m4])
+AC_OUTPUT
+END
+
+echo AM_PATH_PYTHON > mypy.m4
+
+$ACLOCAL
+$AUTOCONF
+
+# Simulate no Python.
+./configure PYTHON=: 2>stderr && { cat stderr >&2; exit 1; }
+cat stderr >&2
+grep 'no suitable Python interpreter found' stderr
+
+# Again, but from the environment this time.
+env PYTHON=: ./configure 2>stderr && { cat stderr >&2; exit 1; }
+cat stderr >&2
+grep 'no suitable Python interpreter found' stderr
+
+# Now try using a custom ACTION-IF-NOT-FOUND.
+
+echo 'AM_PATH_PYTHON(,, [echo "$PYTHON" > py])' > mypy.m4
+$AUTOCONF --force
+./configure PYTHON=:
+test x"$(cat py)" = x:
+
+# Now try requiring a version.
+
+rm -rf autom4te*.cache # Will have to re-run aclocal.
+
+# Hopefully the Python team will never release such a version :-)
+echo 'AM_PATH_PYTHON([9999.9], [])' > mypy.m4
+$ACLOCAL
+$AUTOCONF
+./configure >stdout 2>stderr && {
+  cat stdout
+  cat stderr >&2
+  exit 1
+}
+cat stdout
+cat stderr >&2
+$EGREP 'checking for a Python interpreter with version >= 9999\.9\.\.\. no(ne)? *$' stdout
+grep 'no suitable Python interpreter found' stderr
+
+# Now try requiring a version and using a custom ACTION-IF-NOT-FOUND.
+
+echo 'AM_PATH_PYTHON([9999.9], [], [echo "$PYTHON" > py])' > mypy.m4
+$AUTOCONF --force
+./configure
+test x"$(cat py)" = x:
+
+:
diff --git a/t/python5b.sh b/t/python-too-old.sh
index 39190d920..e4185fcd2 100755
--- a/t/python5b.sh
+++ b/t/python-too-old.sh
@@ -14,18 +14,39 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Test detection of missing Python.
-# Same as python5.test, but with the user forcing the python to use.
+# Test detection of too old Python, also forcing the python to use.
+# See also related test 't/python-am-path-missing.sh'.
 
+am_create_testdir=empty
 required=python
 . ./defs || exit 1
 
-cat >>configure.ac << 'END'
+py_too_old ()
+{
+  ./configure ${1+"PYTHON=$1"} >stdout 2>stderr && {
+    cat stdout
+    cat stderr >&2
+    exit 1
+  }
+  cat stdout
+  cat stderr >&2
+  grep "whether $1 version is >= 9999\\.9\\.\\.\\. no *$" stdout
+  grep '[Pp]ython interpreter is too old' stderr
+}
+
+PYTHON=; unset PYTHON
+
+cat > configure.ac <<END
+AC_INIT([$me], [1.0])
 # Hopefully the Python team will never release such a version.
 AM_PATH_PYTHON([9999.9])
-AC_OUTPUT
 END
 
+$ACLOCAL
+$AUTOCONF
+
+py_too_old python
+
 mkdir bin
 cat > bin/my-python << 'END'
 #! /bin/sh
@@ -34,20 +55,6 @@ END
 chmod a+x bin/my-python
 PATH=$(pwd)/bin$PATH_SEPARATOR$PATH
 
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-./configure PYTHON=my-python >stdout 2>stderr && {
-  cat stdout
-  cat stderr >&2
-  exit 1
-}
-cat stdout
-cat stderr >&2
-grep 'whether my-python version is >= 9999\.9\.\.\. no *$' stdout
-grep '[Pp]ython interpreter is too old' stderr
+py_too_old my-python
 
 :
diff --git a/t/python-vars.sh b/t/python-vars.sh
index 35cd5d700..5bac2803b 100755
--- a/t/python-vars.sh
+++ b/t/python-vars.sh
@@ -29,7 +29,7 @@ PYTHON=python
 # Note that the value of the 'pythondir' and 'pyexecdir' variables can
 # vary among different python installations, so we need more relaxed
 # and ad-hoc checks for them.  Also, more proper "functional" checks
-# on them should be done in the 'python-virtualenv.test' test.
+# on them should be done in the 'python-virtualenv.sh' test.
 PYTHON_VERSION=$($PYTHON -c 'import sys; print(sys.version[:3])') || exit 1
 PYTHON_PLATFORM=$($PYTHON -c 'import sys; print(sys.platform)') || exit 1
 PYTHON_EXEC_PREFIX='${exec_prefix}'
diff --git a/t/python4.sh b/t/python4.sh
deleted file mode 100755
index d084861d5..000000000
--- a/t/python4.sh
+++ /dev/null
@@ -1,43 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2003-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# Test detection of missing Python.
-
-# Python is not required for this test.
-. ./defs || exit 1
-
-cat >>configure.ac <<EOF
-AM_PATH_PYTHON
-AC_OUTPUT
-EOF
-
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-# Simulate no Python.
-./configure PYTHON=: 2>stderr && { cat stderr >&2; exit 1; }
-cat stderr >&2
-grep 'no suitable Python interpreter found' stderr
-
-# Again, but from the environment this time.
-env PYTHON=: ./configure 2>stderr && { cat stderr >&2; exit 1; }
-cat stderr >&2
-grep 'no suitable Python interpreter found' stderr
-
-:
diff --git a/t/python5.sh b/t/python5.sh
deleted file mode 100755
index 8e1e03089..000000000
--- a/t/python5.sh
+++ /dev/null
@@ -1,45 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2003-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# Test detection of missing Python.
-# Same as python4.test, but requiring a version.
-
-# Python is not required for this test.
-. ./defs || exit 1
-
-cat >>configure.ac <<EOF
-# Hopefully the Python team will never release such a version.
-AM_PATH_PYTHON([9999.9])
-AC_OUTPUT
-EOF
-
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-./configure >stdout 2>stderr && {
-  cat stdout
-  cat stderr >&2
-  exit 1
-}
-cat stdout
-cat stderr >&2
-$EGREP 'checking for a Python interpreter with version >= 9999\.9\.\.\. no(ne)? *$' stdout
-grep 'no suitable Python interpreter found' stderr
-
-:
diff --git a/t/python6.sh b/t/python6.sh
deleted file mode 100755
index b2bc7dae6..000000000
--- a/t/python6.sh
+++ /dev/null
@@ -1,38 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2003-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# Test detection of missing Python.
-# Same as python4.test, but using a custom ACTION-IF-NOT-FOUND.
-
-# Python is not required for this test.
-. ./defs || exit 1
-
-cat >>configure.ac <<\EOF
-AM_PATH_PYTHON(,, [echo "$PYTHON" > py])
-AC_OUTPUT
-EOF
-
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-# Simulate no Python.
-./configure PYTHON=:
-test x"$(cat py)" = x:
-
-:
diff --git a/t/python7.sh b/t/python7.sh
deleted file mode 100755
index b3b1421fd..000000000
--- a/t/python7.sh
+++ /dev/null
@@ -1,38 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2003-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# Test detection of missing Python.
-# Same as python6.test, but requiring a version.
-
-# Python is not required for this test.
-. ./defs || exit 1
-
-cat >>configure.ac <<\EOF
-# Hopefully the Python team will never release such a version.
-AM_PATH_PYTHON([9999.9], [], [echo "$PYTHON" > py])
-AC_OUTPUT
-EOF
-
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-./configure
-test x"$(cat py)" = x:
-
-:
diff --git a/t/python8.sh b/t/python8.sh
deleted file mode 100755
index dd1174a3c..000000000
--- a/t/python8.sh
+++ /dev/null
@@ -1,37 +0,0 @@
-#! /bin/sh
-# Copyright (C) 2003-2012 Free Software Foundation, Inc.
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-# Test ACTION-IF-TRUE in AM_PATH_PYTHON.
-
-required=python
-. ./defs || exit 1
-
-cat >>configure.ac <<'EOF'
-# $PYTHON is supposed to be properly set in ACTION-IF-TRUE.
-AM_PATH_PYTHON(, [$PYTHON -V >py-version 2>&1])
-AC_OUTPUT
-EOF
-
-: > Makefile.am
-
-$ACLOCAL
-$AUTOCONF
-$AUTOMAKE --add-missing
-
-./configure
-grep '^Python [0-9]\.[0-9][0-9]*\.[0-9]' py-version
-
-:
diff --git a/t/remake-all-1.sh b/t/remake-all-1.sh
index 9596ba801..93a870eb7 100755
--- a/t/remake-all-1.sh
+++ b/t/remake-all-1.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check that the "all" target triggers rebuilt of outdated Makefiles.
-# See also sister test 'remake-all-2.test'.
+# See also sister test 'remake-all-2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-all-2.sh b/t/remake-all-2.sh
index 2fad99e79..0f7d9849a 100755
--- a/t/remake-all-2.sh
+++ b/t/remake-all-2.sh
@@ -16,7 +16,7 @@
 
 # Check that the "all" target triggers rebuilt of outdated makefiles.
 # This handle the case in which the makefiles are not called 'Makefile'.
-# See also sister test 'remake-all-1.test'.
+# See also sister test 'remake-all-1.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-deleted-m4-file.sh b/t/remake-deleted-m4-file.sh
index 312d0f9ba..0bb7cae6f 100755
--- a/t/remake-deleted-m4-file.sh
+++ b/t/remake-deleted-m4-file.sh
@@ -18,7 +18,7 @@
 # defined get inlined into the caller.  Try with both an indirect
 # call and a direct one.  This can be seen as testing the "deleted
 # header file" issue w.r.t. aclocal.m4 dependencies.  See also related
-# test 'acloca22.test'.
+# test 'acloca22.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-renamed-m4-macro-and-file.sh b/t/remake-renamed-m4-macro-and-file.sh
index 89d216472..f440a45e4 100755
--- a/t/remake-renamed-m4-macro-and-file.sh
+++ b/t/remake-renamed-m4-macro-and-file.sh
@@ -16,7 +16,7 @@
 
 # Test remake rules when an m4 file gets renamed and *simultaneously*
 # an m4 macro in it gets renamed.  Kudos to Bruno Haible for thinking
-# about this situation.  See also related test 'acloca22.test'.
+# about this situation.  See also related test 'acloca22.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-subdir-from-subdir.sh b/t/remake-subdir-from-subdir.sh
index e9bde45bf..b6c0c61b8 100755
--- a/t/remake-subdir-from-subdir.sh
+++ b/t/remake-subdir-from-subdir.sh
@@ -16,8 +16,8 @@
 
 # Check that remake rules works for adding a new subdirectory from a
 # pre-existing subdirectory.
-# See also the other similar tests 'remake-subdir*.test', and the
-# related test 'aclocal5.test'.
+# See also the other similar tests 'remake-subdir*.sh', and the
+# related test 'aclocal5.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-subdir-gnu.sh b/t/remake-subdir-gnu.sh
index 24d5c4c0a..9b2672bec 100755
--- a/t/remake-subdir-gnu.sh
+++ b/t/remake-subdir-gnu.sh
@@ -17,8 +17,8 @@
 # Check that remake rules works from subdirectories, even using
 # 'GNUmakefile' as makefiles name.  This obviously requires GNU
 # make.
-# See also the other similar tests 'remake-subdir*.test', and the
-# related test 'aclocal5.test'
+# See also the other similar tests 'remake-subdir*.sh', and the
+# related test 'aclocal5.sh'
 
 required=GNUmake
 . ./defs || exit 1
diff --git a/t/remake-subdir.sh b/t/remake-subdir.sh
index 5026d1684..1e4716d8f 100755
--- a/t/remake-subdir.sh
+++ b/t/remake-subdir.sh
@@ -16,8 +16,8 @@
 
 # Check that remake rules works from subdirectories, even with non-GNU
 # make implementations.
-# See also the other similar tests 'remake-subdir*.test', and the
-# related test 'aclocal5.test'.
+# See also the other similar tests 'remake-subdir*.sh', and the
+# related test 'aclocal5.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake-subdir2.sh b/t/remake-subdir2.sh
index a14a2f1c1..42f0ba14d 100755
--- a/t/remake-subdir2.sh
+++ b/t/remake-subdir2.sh
@@ -16,8 +16,8 @@
 
 # Check that remake rules works from subdirectories, even when makefiles
 # are not named "Makefile".
-# See also the other similar tests 'remake-subdir*.test', and the
-# related test 'aclocal5.test'.
+# See also the other similar tests 'remake-subdir*.sh', and the
+# related test 'aclocal5.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake.sh b/t/remake.sh
index b883d2ad5..bd39792a2 100755
--- a/t/remake.sh
+++ b/t/remake.sh
@@ -16,7 +16,7 @@
 
 # Weak "grepping" test trying to ensure that remaking rules in a subdir
 # are correctly generated.
-# See also sister functional test 'remake1a.test'.
+# See also sister functional test 'remake1a.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake10a.sh b/t/remake10a.sh
index 830d6ca2b..e91503bbd 100755
--- a/t/remake10a.sh
+++ b/t/remake10a.sh
@@ -16,7 +16,7 @@
 
 # Test remake rules for m4 files included (also recursively) by
 # configure.ac.
-# Keep in sync with sister tests 'remake10b.test' and 'remake10c.test'.
+# Keep in sync with sister tests 'remake10b.sh' and 'remake10c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake10b.sh b/t/remake10b.sh
index 7aeab7916..2c6e22a5d 100755
--- a/t/remake10b.sh
+++ b/t/remake10b.sh
@@ -16,7 +16,7 @@
 
 # Test remake rules for am files included (also recursively) by
 # Makefile.am.
-# Keep in sync with sister tests 'remake10a.test' and 'remake10c.test'.
+# Keep in sync with sister tests 'remake10a.sh' and 'remake10c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake10c.sh b/t/remake10c.sh
index 97c8745c0..7ac0ae653 100755
--- a/t/remake10c.sh
+++ b/t/remake10c.sh
@@ -16,7 +16,7 @@
 
 # Test remake rules for m4 files included (also recursively) by
 # aclocal.m4.
-# Keep in sync with sister tests 'remake10a.test' and 'remake10b.test'.
+# Keep in sync with sister tests 'remake10a.sh' and 'remake10b.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake1a.sh b/t/remake1a.sh
index 6460fc3cc..cdf494aad 100755
--- a/t/remake1a.sh
+++ b/t/remake1a.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Make sure remaking rules in subdir are correctly generated.
-# See also sister "grepping" test 'remake.test'.
+# See also sister "grepping" test 'remake.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake3.sh b/t/remake3.sh
index e19d8ea73..712badc73 100755
--- a/t/remake3.sh
+++ b/t/remake3.sh
@@ -16,7 +16,7 @@
 
 # Weak "grepping" test trying to ensure that remake rules work for files
 # in a subdirectory even when there is no Makefile for that subdirectory.
-# See also sister functional test 'remake3a.test'.
+# See also sister functional test 'remake3a.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake3a.sh b/t/remake3a.sh
index 9cbd10553..0f2407a13 100755
--- a/t/remake3a.sh
+++ b/t/remake3a.sh
@@ -16,7 +16,7 @@
 
 # Ensure that remake rules work for files in a subdirectory even when
 # there is no Makefile for that subdirectory.
-# See also sister "grepping" test 'remake3.test'.
+# See also sister "grepping" test 'remake3.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake8a.sh b/t/remake8a.sh
index b720bd26c..5ec642dcc 100755
--- a/t/remake8a.sh
+++ b/t/remake8a.sh
@@ -18,7 +18,7 @@
 # This testcase checks dependency of generated Makefile from Makefile.am,
 # configure.ac, acinclude.m4, aclocal.m4, and extra m4 files considered
 # by aclocal.
-# Keep this in sync with sister test 'remake8b.test', which performs the
+# Keep this in sync with sister test 'remake8b.sh', which performs the
 # same checks for a VPATH build.
 
 . ./defs || exit 1
@@ -43,7 +43,7 @@ $ACLOCAL
 $AUTOCONF
 $AUTOMAKE
 
-srcdir='.' # To make syncing with remake8b.test easier.
+srcdir='.' # To make syncing with remake8b.sh easier.
 
 $srcdir/configure
 
diff --git a/t/remake8b.sh b/t/remake8b.sh
index 19fb9857a..9dca90e27 100755
--- a/t/remake8b.sh
+++ b/t/remake8b.sh
@@ -18,7 +18,7 @@
 # This testcase checks dependency of generated Makefile from Makefile.am,
 # configure.ac, acinclude.m4, aclocal.m4, and extra m4 files considered
 # by aclocal.
-# Keep this in sync with sister test 'remake8a.test', which performs the
+# Keep this in sync with sister test 'remake8a.sh', which performs the
 # same checks for a in-tree build.
 
 . ./defs || exit 1
@@ -45,7 +45,7 @@ $AUTOMAKE
 
 mkdir build
 cd build
-srcdir='..' # To make syncing with remake8a.test easier.
+srcdir='..' # To make syncing with remake8a.sh easier.
 
 $srcdir/configure
 
diff --git a/t/remake9a.sh b/t/remake9a.sh
index 3e811b766..3e239c9c3 100755
--- a/t/remake9a.sh
+++ b/t/remake9a.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test remake rules when configure.ac or its prerequisites change.
-# Keep in sync with the other sister tests 'remake9*.test'.
+# Keep in sync with the other sister tests 'remake9*.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake9b.sh b/t/remake9b.sh
index c90a9820e..aee41c4c4 100755
--- a/t/remake9b.sh
+++ b/t/remake9b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test remake rules when Makefile.am or its prerequisites change.
-# Keep in sync with the other sister tests 'remake9*.test'.
+# Keep in sync with the other sister tests 'remake9*.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake9c.sh b/t/remake9c.sh
index c39bac1f9..402bef9c9 100755
--- a/t/remake9c.sh
+++ b/t/remake9c.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test remake rules when acinclude.m4 or its prerequisites change.
-# Keep in sync with the other sister tests 'remake9*.test'.
+# Keep in sync with the other sister tests 'remake9*.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/remake9d.sh b/t/remake9d.sh
index 23441ac5d..1cf3fdf36 100755
--- a/t/remake9d.sh
+++ b/t/remake9d.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test remake rules when aclocal.m4 or its prerequisites change.
-# Keep in sync with the other sister tests 'remake9*.test'.
+# Keep in sync with the other sister tests 'remake9*.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/silent-many-gcc.sh b/t/silent-many-gcc.sh
index 433aaa62d..2e5d203d7 100755
--- a/t/silent-many-gcc.sh
+++ b/t/silent-many-gcc.sh
@@ -15,11 +15,11 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check silent-rules mode, with gcc depmode and many languages at once.
-# This test partly overlaps with other silent*.test, but it serves as
+# This test partly overlaps with other 'silent*.sh', but it serves as
 # a stress test by using many different languages at once -- so don't
 # remove this test script.
 # This test requires the GNU compilers; keep it in sync with sister test
-# 'silent-many-generic.test', which should work with generic compilers.
+# 'silent-many-generic.sh', which should work with generic compilers.
 
 required='gcc g++ gfortran lex yacc'
 . ./defs || exit 1
@@ -204,7 +204,7 @@ $FGREP 'fo2-foo6.c' Makefile.in
 depmodes="am_cv_CC_dependencies_compiler_type=gcc \
           am_cv_CXX_dependencies_compiler_type=gcc"
 # This apparently useless "for" loop is here to simplify the syncing
-# with sister test 'silent-many-generic.test'.
+# with sister test 'silent-many-generic.sh'.
 for config_args in \
   "$depmodes"
 do
diff --git a/t/silent-many-generic.sh b/t/silent-many-generic.sh
index 0837a5da6..7d18c5778 100755
--- a/t/silent-many-generic.sh
+++ b/t/silent-many-generic.sh
@@ -15,11 +15,11 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check silent-rules mode, with many languages at once.
-# This test partly overlaps with other silent*.test, but it serves as
+# This test partly overlaps with other 'silent*.sh', but it serves as
 # a stress test by using many different languages at once -- so don't
 # remove this test script.
 # This test should work with generic compilers; keep it in sync with
-# sister test 'silent-many-gcc.test', which requires the GNU compilers
+# sister test 'silent-many-gcc.sh', which requires the GNU compilers
 # and forces the use of gcc depmode.
 
 required='cc c++ fortran fortran77 lex yacc'
diff --git a/t/silent-yacc.sh b/t/silent-yacc.sh
index 779f49834..9283b325a 100755
--- a/t/silent-yacc.sh
+++ b/t/silent-yacc.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check silent-rules mode for Yacc.
-# Keep this in sync with sister test 'silent-yacc-gcc.test'.
+# Keep this in sync with sister test 'silent-yacc-gcc.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/silent.sh b/t/silent.sh
index 633cdd8a8..410e51c80 100755
--- a/t/silent.sh
+++ b/t/silent.sh
@@ -16,7 +16,7 @@
 
 # Check silent-rules mode, without libtool, standard depmode case.
 
-# Please keep this file in sync with silent2.test.
+# Please keep this file in sync with 'silent2.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/silent2.sh b/t/silent2.sh
index 1d67f7e0f..25cf8b140 100755
--- a/t/silent2.sh
+++ b/t/silent2.sh
@@ -17,7 +17,7 @@
 # Check silent-rules mode, without libtool, non-fastdep case
 # (so that, with GCC, we also cover the other code paths in depend2).
 
-# Please keep this file in sync with silent.test.
+# Please keep this file in sync with 'silent.sh'.
 
 required=gcc
 . ./defs || exit 1
diff --git a/t/silent3.sh b/t/silent3.sh
index fe27ae40b..f5dd83410 100755
--- a/t/silent3.sh
+++ b/t/silent3.sh
@@ -16,7 +16,7 @@
 
 # Check silent-rules mode, with libtool, standard depmode case.
 
-# Please keep this file in sync with silent4.test and silent9.test.
+# Please keep this file in sync with 'silent4.sh' and 'silent9.sh'.
 
 required='cc libtoolize'
 . ./defs || exit 1
diff --git a/t/silent4.sh b/t/silent4.sh
index 88049f16f..8dcad3dfe 100755
--- a/t/silent4.sh
+++ b/t/silent4.sh
@@ -17,7 +17,7 @@
 # Check silent-rules mode, with libtool, non-fastdep case
 # (so that, with GCC, we also cover the other code paths in depend2).
 
-# Please keep this file in sync with silent3.test and silent9.test.
+# Please keep this file in sync with 'silent3.sh' and 'silent9.sh'.
 
 required="libtoolize gcc"
 . ./defs || exit 1
diff --git a/t/silent9.sh b/t/silent9.sh
index c2868b500..8d0f6ea87 100755
--- a/t/silent9.sh
+++ b/t/silent9.sh
@@ -16,7 +16,7 @@
 
 # Check silent-rules mode, with libtool, nodep case.
 
-# Please keep this file in sync with silent3.test and silent4.test.
+# Please keep this file in sync with 'silent3.sh' and 'silent4.sh'.
 
 required='cc libtoolize'
 . ./defs || exit 1
diff --git a/t/silentcxx-gcc.sh b/t/silentcxx-gcc.sh
index 903378c64..bafad6dcf 100755
--- a/t/silentcxx-gcc.sh
+++ b/t/silentcxx-gcc.sh
@@ -16,7 +16,7 @@
 
 # Check silent-rules mode for C++.
 # This test requires the GNU C++ compiler; keep it in sync with sister
-# test 'silentcxx.test', which should work with generic compilers.
+# test 'silentcxx.sh', which should work with generic compilers.
 
 required=g++
 . ./defs || exit 1
@@ -68,7 +68,7 @@ $FGREP am_cv_CXX_dependencies_compiler_type configure
 
 # Force gcc ("fast") depmode.
 # This apparently useless "for" loop is here to simplify the syncing
-# with sister test 'silentcxx.test'.
+# with sister test 'silentcxx.sh'.
 for config_args in \
   am_cv_CXX_dependencies_compiler_type=gcc
 do
diff --git a/t/silentcxx.sh b/t/silentcxx.sh
index a3c375a22..fe4c9d4a9 100755
--- a/t/silentcxx.sh
+++ b/t/silentcxx.sh
@@ -16,7 +16,7 @@
 
 # Check silent-rules mode for C++.
 # This test should work with generic C++ compilers; keep it in sync with
-# sister test 'silentcxx-gcc.test', which requires the GNU C++ compiler
+# sister test 'silentcxx-gcc.sh', which requires the GNU C++ compiler
 # and forces the use of gcc depmode.
 
 required=c++
diff --git a/t/silentf77.sh b/t/silentf77.sh
index a50c69eaa..e104a69d7 100755
--- a/t/silentf77.sh
+++ b/t/silentf77.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check silent-rules mode for Fortran 77.
-# Keep this ins sync with the sister test silentf90.test.
+# Keep this ins sync with the sister test 'silentf90.sh'.
 
 required=fortran77
 . ./defs || exit 1
diff --git a/t/silentf90.sh b/t/silentf90.sh
index 78bbce9ff..f0c470dba 100755
--- a/t/silentf90.sh
+++ b/t/silentf90.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check silent-rules mode for Fortran 90.
-# Keep this ins sync with the sister test silentf77.test.
+# Keep this ins sync with the sister test 'silentf77.sh'.
 
 required=fortran
 . ./defs || exit 1
diff --git a/t/subdir-ac-subst.sh b/t/subdir-ac-subst.sh
index 48b4b0dbe..a8deb17a6 100755
--- a/t/subdir-ac-subst.sh
+++ b/t/subdir-ac-subst.sh
@@ -16,7 +16,7 @@
 
 # The for conditional SUBDIRS.
 # SUBDIRS + AC_SUBST setup from the manual.
-# Lots of lines here are duplicated in subcond-am-cond.test.
+# Lots of lines here are duplicated in 'subcond-am-cond.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/subdir-add-pr46.sh b/t/subdir-add-pr46.sh
index 2a9049cec..66ecfda7a 100755
--- a/t/subdir-add-pr46.sh
+++ b/t/subdir-add-pr46.sh
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure that adding a new directory works.
-# This test runs 'make' from the top-level directory, the sister test
-# 'subdir8.test' do it from a subdirectory.
+# This test runs 'make' from the top-level directory, the sister
+# test 'subdir-add2-pr46.sh' do it from a subdirectory.
 # PR automake/46
 
 . ./defs || exit 1
@@ -36,9 +36,10 @@ $MAKE
 # Now add new directories.
 
 # First we add a new directory by modifying configure.ac directly.
-# We update configure.ac *before* updating sub/Makefile.am; subdir8.test
-# does it in the other way: it updates confiles.m4 (which is m4_included
-# by configure.ac there) after Makefile.am.
+# We update configure.ac *before* updating sub/Makefile.am; the sister
+# test 'subdir-add2-pr46.sh' does it in the other way: it updates
+# confiles.m4 (which is m4_included by configure.ac there) after
+# Makefile.am.
 
 # Modified configure dependencies must be newer than config.status.
 $sleep
diff --git a/t/subdir-add2-pr46.sh b/t/subdir-add2-pr46.sh
index b226a09f2..a4020525d 100755
--- a/t/subdir-add2-pr46.sh
+++ b/t/subdir-add2-pr46.sh
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure that adding a new directory works, even from
-# subdirectories.  The sister test 'subdir5.test' makes sure it works
-# when make is run from the top-level directory.
+# subdirectories.  The sister test 'subdir-add-pr46.sh' makes sure
+# it works when make is run from the top-level directory.
 # PR automake/46
 
 . ./defs || exit 1
@@ -49,10 +49,10 @@ $MAKE
 
 # Now add new directories.
 
-# The first step users typically do when adding a new subdir is
-# editing configure.ac.  That is already tested by subdir5.test,
-# though, so here we try to just edit a file that is included by
-# configure.ac, without touching configure.ac itself.
+# The first step users typically do when adding a new subdir is editing
+# configure.ac.  That is already tested by 'subdir-add-pr46.sh' though,
+# so here we try to just edit a file that is included by configure.ac,
+# without touching configure.ac itself.
 
 mkdir sub/maude
 cat > sub/maude/Makefile.am << 'END'
@@ -66,10 +66,10 @@ echo 'SUBDIRS = maude' >> sub/Makefile.am
 mkdir maude
 : > maude/Makefile.am
 
-# Update confiles.m4 *after* updating sub/Makefile.am; subdir5.test do
-# it in the other way: it updates configure.ac before Makefile.am.
-# We sleep here because modified configure dependencies must be newer
-# than config.status.
+# Update confiles.m4 *after* updating sub/Makefile.am; the sister test
+# 'subdir-add-pr46.sh' does it the in other way: it updates configure.ac
+# before Makefile.am.  We sleep here because modified configure
+# dependencies must be newer than config.status.
 $sleep
 echo 'AC_CONFIG_FILES([maude/Makefile sub/maude/Makefile])' >> confiles.m4
 
diff --git a/t/subdir-am-cond.sh b/t/subdir-am-cond.sh
index 7ad605957..cb55ffb88 100755
--- a/t/subdir-am-cond.sh
+++ b/t/subdir-am-cond.sh
@@ -16,7 +16,7 @@
 
 # The for conditional SUBDIRS.
 # SUBDIRS + AM_CONDITIONAL setup from the manual.
-# Lots of lines here are duplicated in subdir-ac-subst.test.
+# Lots of lines here are duplicated in 'subdir-ac-subst.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/subobj11a.sh b/t/subobj11a.sh
index 474ed82fc..25bdb93d1 100755
--- a/t/subobj11a.sh
+++ b/t/subobj11a.sh
@@ -23,8 +23,8 @@
 # (even if the file 'foo.mk' exists). The error disappear by collapsing
 # the repeated slash '/' characters into a single one.
 #
-# See also sister "grepping" test 'subobj11b.test', and related test
-# 'subobj11c.test'.
+# See also sister "grepping" test 'subobj11b.sh', and related test
+# 'subobj11c.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/subobj11b.sh b/t/subobj11b.sh
index b1495b08b..6d539c2c3 100755
--- a/t/subobj11b.sh
+++ b/t/subobj11b.sh
@@ -23,8 +23,8 @@
 # (even if the file 'foo.mk' exists). The error disappear by collapsing
 # the repeated slash '/' characters into a single one.
 #
-# See also "semantic" sister test 'subobj11a.test', and related test
-# 'subobj11c.test'.
+# See also "semantic" sister test 'subobj11a.sh', and related test
+# 'subobj11c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/subobj11c.sh b/t/subobj11c.sh
index 0b47c2eb9..ce33e3086 100755
--- a/t/subobj11c.sh
+++ b/t/subobj11c.sh
@@ -17,7 +17,7 @@
 # Automatic dependency tracking with subdir-objects option active:
 # check for a pathological case of slash-collapsing in the name of
 # included makefile fragments (containing dependency info).
-# See also related tests 'subobj11a.test' and 'subobj11b.test'.
+# See also related tests 'subobj11a.sh' and 'subobj11b.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/subst3.sh b/t/subst3.sh
index 8ee3324f3..18c17e2e2 100755
--- a/t/subst3.sh
+++ b/t/subst3.sh
@@ -14,7 +14,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Test installation with substitutions.  This test is based on nobase.test.
+# Test installation with substitutions.  This test is based on
+# 'nobase.sh'.
 
 required=cc
 . ./defs || exit 1
diff --git a/t/suffix.sh b/t/suffix.sh
index 28191b7ca..cf7ea1050 100755
--- a/t/suffix.sh
+++ b/t/suffix.sh
@@ -16,7 +16,7 @@
 
 # Make sure proper suffix rules for C compilation are produced, and
 # only once.
-# See also related test 'suffix2.test'.
+# See also related test 'suffix2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/suffix2.sh b/t/suffix2.sh
index 8ac0431c0..1cee87534 100755
--- a/t/suffix2.sh
+++ b/t/suffix2.sh
@@ -16,7 +16,7 @@
 
 # Make sure proper suffix rules for C compilation are produced,
 # and only once, even for libtool libraries.
-# See also related test 'suffix.test'.
+# See also related test 'suffix.sh'.
 required=libtoolize
 
 . ./defs || exit 1
diff --git a/t/suffix6.sh b/t/suffix6.sh
index 4ca09f497..4b3dee20d 100755
--- a/t/suffix6.sh
+++ b/t/suffix6.sh
@@ -16,8 +16,8 @@
 
 # Test to make sure Automake supports implicit rules with dot-less
 # extensions.  Also make sure that '.o' and '.obj' are handled like
-# '.$(OBJEXT)'.  See also related "semantic" tests suffix6b.test
-# and suffix6c.test.
+# '.$(OBJEXT)'.  See also related "semantic" tests 'suffix6b.sh'
+# and 'suffix6c.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/suffix6b.sh b/t/suffix6b.sh
index bb11cdfea..cfd166215 100755
--- a/t/suffix6b.sh
+++ b/t/suffix6b.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure Automake supports implicit rules with dot-less
-# extensions.  Se also related "grepping" test suffix6.test.
+# extensions.  Se also related "grepping" test 'suffix6.sh'.
 
 required=GNUmake # Other makes might not grok dot-less suffix rules.
 . ./defs || exit 1
diff --git a/t/suffix6c.sh b/t/suffix6c.sh
index 7500543d1..f688ef779 100755
--- a/t/suffix6c.sh
+++ b/t/suffix6c.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure that '.o' and '.obj' are handled like '.$(OBJEXT)'.
-# See also related "grepping" test suffix6.test.
+# See also related "grepping" test 'suffix6.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-ambiguous-directive.sh b/t/tap-ambiguous-directive.sh
index aaf2cd06d..63544e3cb 100755
--- a/t/tap-ambiguous-directive.sh
+++ b/t/tap-ambiguous-directive.sh
@@ -16,7 +16,7 @@
 
 # TAP support:
 #  - handling of "ambiguous" TODO and SKIP directives
-# See also related test 'tap-todo-skip-together.test'.
+# See also related test 'tap-todo-skip-together.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-fancy.sh b/t/tap-fancy.sh
index 9ca50217a..c59d0c1e5 100755
--- a/t/tap-fancy.sh
+++ b/t/tap-fancy.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # TAP support: some unusual forms for valid TAP input.
-# See also related test 'tap-fancy2.test'.
+# See also related test 'tap-fancy2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-fancy2.sh b/t/tap-fancy2.sh
index d69cf5035..1a3ab024f 100755
--- a/t/tap-fancy2.sh
+++ b/t/tap-fancy2.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # TAP support: more unusual forms for valid TAP input.
-# See also related test 'tap-fancy.test'.
+# See also related test 'tap-fancy.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-log.sh b/t/tap-log.sh
index 2e92f2153..b9d360301 100755
--- a/t/tap-log.sh
+++ b/t/tap-log.sh
@@ -20,7 +20,7 @@
 #  - stdout and stderr of a script go in its log file
 #  - TEST_SUITE_LOG redefinition, at either automake or make time
 #  - VERBOSE environment variable support
-# Keep in sync with 'test-log.test'.
+# Keep in sync with 'test-log.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-no-spurious.sh b/t/tap-no-spurious.sh
index bc98a0900..d8bf5eefe 100755
--- a/t/tap-no-spurious.sh
+++ b/t/tap-no-spurious.sh
@@ -83,7 +83,7 @@ set -x # Reset shell xtraces.
 
 # The prove(1) utility doesn't bail out on these, so our driver
 # shouldn't either.
-# See comments in 'tap-bailout-leading-space.test' for an explanation
+# See comments in 'tap-bailout-leading-space.sh' for an explanation
 # of why we don't have a whitespace-prepended "Bail out!" line here.
 cat >> all.test <<'END'
 bailout
diff --git a/t/tap-passthrough-exit.sh b/t/tap-passthrough-exit.sh
index f6507e0f4..33287be90 100755
--- a/t/tap-passthrough-exit.sh
+++ b/t/tap-passthrough-exit.sh
@@ -17,7 +17,7 @@
 # TAP support:
 #  - non-success exit status of a test script is reported in the
 #    log file
-# See also related test 'tap-passthrough.test'.
+# See also related test 'tap-passthrough.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-passthrough.sh b/t/tap-passthrough.sh
index e2eae177f..981c42852 100755
--- a/t/tap-passthrough.sh
+++ b/t/tap-passthrough.sh
@@ -18,7 +18,7 @@
 #  - all input (valid TAP lines, invalid TAP lines, non-TAP lines)
 #    are passed through in the log file
 #  - TAP errors are reported in the log file too
-# See also related test 'tap-passthrough-exit.test'.
+# See also related test 'tap-passthrough-exit.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-plan-errors.sh b/t/tap-plan-errors.sh
index 4b6a4105f..dd37aff08 100755
--- a/t/tap-plan-errors.sh
+++ b/t/tap-plan-errors.sh
@@ -19,9 +19,9 @@
 #  - multiple test plans
 #  - missing test plan
 #  - misplaced test plan (tests run after a late plan)
-# Checks about unplanned tests are performed in 'tap-unplanned.test'
-# and 'tap-skip-whole-badcount.test'.  More checks about corner-cases
-# in TAP plans are performed in 'tap-plan-corner.test'.
+# Checks about unplanned tests are performed in 'tap-unplanned.sh'
+# and 'tap-skip-whole-badcount.sh'.  More checks about corner-cases
+# in TAP plans are performed in 'tap-plan-corner.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-recheck.sh b/t/tap-recheck.sh
index 3c542ba8b..a5679645c 100755
--- a/t/tap-recheck.sh
+++ b/t/tap-recheck.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test the 'recheck' target for TAP test protocol.
-# Keep in sync with 'test-driver-custom-multitest-recheck.test'.
+# Keep in sync with 'test-driver-custom-multitest-recheck.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-todo-skip-together.sh b/t/tap-todo-skip-together.sh
index dc9e160b3..ee400585f 100755
--- a/t/tap-todo-skip-together.sh
+++ b/t/tap-todo-skip-together.sh
@@ -16,7 +16,7 @@
 
 # TAP support:
 #  - TODO and SKIP directives on the same line: the first one wins
-# See also related test 'tap-ambiguous-directive.test'.
+# See also related test 'tap-ambiguous-directive.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/tap-whitespace-normalization.sh b/t/tap-whitespace-normalization.sh
index 0cbf90bc4..c907d115b 100755
--- a/t/tap-whitespace-normalization.sh
+++ b/t/tap-whitespace-normalization.sh
@@ -18,7 +18,7 @@
 # progress output on console.  We keep all of these checks here in a single
 # script so that a potential cosmetic change in the output format won't
 # force us to tweak dozens of other tests (hopefully).
-# See also related test 'tap-todo-skip-whitespace.test'.
+# See also related test 'tap-todo-skip-whitespace.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/test-driver-custom-multitest-recheck.sh b/t/test-driver-custom-multitest-recheck.sh
index 362abbff0..9d3f28f81 100755
--- a/t/test-driver-custom-multitest-recheck.sh
+++ b/t/test-driver-custom-multitest-recheck.sh
@@ -18,9 +18,9 @@
 # that allow multiple testcases in a single test script.  This test not
 # only checks implementation details in Automake's custom test drivers
 # support, but also serves as a "usability test" for our APIs.
-# See also related tests 'test-driver-custom-multitest-recheck2.test'
-# and 'parallel-tests-recheck-override.test'.
-# Keep in sync with 'tap-recheck.test'.
+# See also related tests 'test-driver-custom-multitest-recheck2.sh'
+# and 'parallel-tests-recheck-override.sh'.
+# Keep in sync with 'tap-recheck.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/test-driver-custom-multitest-recheck2.sh b/t/test-driver-custom-multitest-recheck2.sh
index b6f543aee..7f20b814e 100755
--- a/t/test-driver-custom-multitest-recheck2.sh
+++ b/t/test-driver-custom-multitest-recheck2.sh
@@ -18,8 +18,8 @@
 # that allow multiple testcases in a single test script.  In particular,
 # check that this still works when we override $(TESTS) and $(TEST_LOGS)
 # at make runtime.
-# See also related tests 'test-driver-custom-multitest-recheck.test' and
-# 'parallel-tests-recheck-override.test'.
+# See also related tests 'test-driver-custom-multitest-recheck.sh' and
+# 'parallel-tests-recheck-override.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/test-log.sh b/t/test-log.sh
index 0ae77b391..0350cce45 100755
--- a/t/test-log.sh
+++ b/t/test-log.sh
@@ -20,7 +20,7 @@
 #  - stdout and stderr of a test script go in its log file
 #  - TEST_SUITE_LOG redefinition, at either automake or make time
 #  - VERBOSE environment variable support
-# Keep in sync with 'tap-log.test'.
+# Keep in sync with 'tap-log.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/test-missing.sh b/t/test-missing.sh
index 7cf1d52af..5db274d7d 100755
--- a/t/test-missing.sh
+++ b/t/test-missing.sh
@@ -16,7 +16,7 @@
 
 # parallel-tests:
 #  - non-existent scripts listed in TESTS get diagnosed
-# See also related test 'test-missing2.test'.
+# See also related test 'test-missing2.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/test-missing2.sh b/t/test-missing2.sh
index e08bf2d50..2ba34798a 100755
--- a/t/test-missing2.sh
+++ b/t/test-missing2.sh
@@ -17,7 +17,7 @@
 # parallel-tests:
 #  - non-existent scripts listed in TESTS get diagnosed, even when
 #    all the $(TEST_LOGS) have a dummy dependency.
-# See also related test 'test-missing.test'.
+# See also related test 'test-missing.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/txinfo23.sh b/t/txinfo23.sh
index 9e47a29d7..c2d582a86 100755
--- a/t/txinfo23.sh
+++ b/t/txinfo23.sh
@@ -16,8 +16,8 @@
 
 # Check that info files are built in builddir when needed.
 # Test with subdir Texinfo.
-# (Similar to txinfo13.test, plus DISTCLEANFILES).
-# (See also txinfo24.test and txinfo25.test).
+# (Similar to txinfo13.sh, plus DISTCLEANFILES).
+# (See also txinfo24.sh and txinfo25.sh).
 
 required='makeinfo tex texi2dvi'
 . ./defs || exit 1
diff --git a/t/txinfo24.sh b/t/txinfo24.sh
index af426d73c..697921508 100755
--- a/t/txinfo24.sh
+++ b/t/txinfo24.sh
@@ -15,8 +15,8 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check that info files are built in builddir when needed.
-# (Similar to txinfo16.test, plus CLEANFILES).
-# (See also txinfo23.test and txinfo25.test).
+# (Similar to txinfo16.sh, plus CLEANFILES).
+# (See also txinfo23.sh and txinfo25.sh).
 
 required='makeinfo tex texi2dvi'
 . ./defs || exit 1
diff --git a/t/txinfo25.sh b/t/txinfo25.sh
index 6eb1975fa..e23f53781 100755
--- a/t/txinfo25.sh
+++ b/t/txinfo25.sh
@@ -17,8 +17,8 @@
 # Check that info files are built in builddir and in srcdir can safely
 # co-exist.  This setup is obtained by having two info files, only one
 # of which being cleaned.
-# (Similar to txinfo16.test, plus CLEANFILES).
-# (See also txinfo23.test and txinfo24.test).
+# (Similar to txinfo16.sh, plus CLEANFILES).
+# (See also txinfo23.sh and txinfo24.sh).
 
 required='makeinfo tex texi2dvi'
 . ./defs || exit 1
diff --git a/t/txinfo28.sh b/t/txinfo28.sh
index f9517fb75..f3517b64f 100755
--- a/t/txinfo28.sh
+++ b/t/txinfo28.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Check that info files are built in builddir when needed.
-# Similar to txinfo24.test, but obfuscating filenames with variable
+# Similar to txinfo24.sh, but obfuscating filenames with variable
 # references.
 # Report from Ralf Corsepius.
 
diff --git a/t/txinfo33.sh b/t/txinfo33.sh
index 037400f43..a55b5ed53 100755
--- a/t/txinfo33.sh
+++ b/t/txinfo33.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # DVIS, PDFS, PSS, HTMLS should not be cleaned upon 'mostlyclean'.
-# Similar to txinfo25.test.
+# Similar to txinfo25.sh.
 
 required='makeinfo tex texi2dvi dvips'
 . ./defs || exit 1
diff --git a/t/vtexi3.sh b/t/vtexi3.sh
index ba50eb362..9afadce05 100755
--- a/t/vtexi3.sh
+++ b/t/vtexi3.sh
@@ -17,7 +17,7 @@
 # Check that vers*.texi files are automatically created and distributed
 # if @included into a texi source.  Also check that they correctly contain
 # the @values definitions they are advertised to.
-# See also the related test 'vtexi4.test', which does similar checks, but
+# See also the related test 'vtexi4.sh', which does similar checks, but
 # for version.texi only, and requires makeinfo, tex and texi2dvi.
 
 . ./defs || exit 1
diff --git a/t/vtexi4.sh b/t/vtexi4.sh
index 8e77e86c2..336ee8617 100755
--- a/t/vtexi4.sh
+++ b/t/vtexi4.sh
@@ -17,7 +17,7 @@
 # Check that the version.texi file is automatically created and distributed
 # if @included into a texi source.  Also check that is correctly defined
 # @values definitions it is advertised to.
-# See also the related test 'vtexi3.test', which does similar checks, but
+# See also the related test 'vtexi3.sh', which does similar checks, but
 # for more vers*.texi files, and does not require makeinfo, tex and
 # texi2dvi.
 
diff --git a/t/yacc-basic.sh b/t/yacc-basic.sh
index 483523532..b1883385b 100755
--- a/t/yacc-basic.sh
+++ b/t/yacc-basic.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Basic semantic checks on Yacc support (without yacc-generated headers).
-# Keep in sync with sister test 'yacc-cxx.test'.
+# Keep in sync with sister test 'yacc-cxx.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yacc-clean-cxx.sh b/t/yacc-clean-cxx.sh
index 20d04d159..f30ce1b2a 100755
--- a/t/yacc-clean-cxx.sh
+++ b/t/yacc-clean-cxx.sh
@@ -18,7 +18,7 @@
 # Yacc sources are cleaned by "make clean", while C++ source and
 # header files derived from distributed Yacc sources are cleaned by
 # "make maintainer-clean".
-# See also sister test 'yacc-clean.test'.
+# See also sister test 'yacc-clean.sh'.
 
 required='c++ yacc'
 . ./defs || exit 1
diff --git a/t/yacc-clean.sh b/t/yacc-clean.sh
index 07b3b790e..dce70a279 100755
--- a/t/yacc-clean.sh
+++ b/t/yacc-clean.sh
@@ -17,7 +17,7 @@
 # Check that .c and .h files derived from non-distributed .y sources
 # are cleaned by "make clean", while .c and .h files derived from
 # distributed .y sources are cleaned by "make maintainer-clean".
-# See also sister test 'yacc-cxx-clean.test'.
+# See also sister test 'yacc-cxx-clean.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yacc-cxx.sh b/t/yacc-cxx.sh
index 24d5546fa..3c1babbfd 100755
--- a/t/yacc-cxx.sh
+++ b/t/yacc-cxx.sh
@@ -16,7 +16,7 @@
 
 # Basic semantic checks on Yacc + C++ support (when yacc-generated
 # headers are not involved).
-# Keep in sync with sister test 'yacc-basic.test'.
+# Keep in sync with sister test 'yacc-basic.sh'.
 
 required='c++ yacc'
 . ./defs || exit 1
diff --git a/t/yacc-d-basic.sh b/t/yacc-d-basic.sh
index 72872f24f..97155a2d5 100755
--- a/t/yacc-d-basic.sh
+++ b/t/yacc-d-basic.sh
@@ -16,7 +16,7 @@
 
 # Tests Yacc support with yacc-generated headers
 # (i.e., '-d' in *YFLAGS).
-# Keep in sync with sister test 'yacc-d-cxx.test'.
+# Keep in sync with sister test 'yacc-d-cxx.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yacc-d-cxx.sh b/t/yacc-d-cxx.sh
index 4165b686d..5bd284e7d 100755
--- a/t/yacc-d-cxx.sh
+++ b/t/yacc-d-cxx.sh
@@ -16,7 +16,7 @@
 
 # Various tests on Yacc/C++ support with yacc-generated headers
 # (i.e., '-d' in *YFLAGS).
-# Keep in sync with sister test 'yacc-d-basic.test'.
+# Keep in sync with sister test 'yacc-d-basic.sh'.
 
 required='c++ yacc'
 . ./defs || exit 1
diff --git a/t/yacc-d-vpath.sh b/t/yacc-d-vpath.sh
index a1950520d..05019fb9e 100755
--- a/t/yacc-d-vpath.sh
+++ b/t/yacc-d-vpath.sh
@@ -20,7 +20,7 @@
 # 'make' and 'make distdir' and check whether the version of 'parse.c'
 # to be distributed is up to date.
 
-# Please keep this in sync with sister test 'yaccvpath.test'.
+# Please keep this in sync with sister test 'yaccvpath.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yacc-line.sh b/t/yacc-line.sh
index 4ef2c011f..525a455b2 100755
--- a/t/yacc-line.sh
+++ b/t/yacc-line.sh
@@ -17,7 +17,7 @@
 # Check that automake yacc support ensures that yacc-generated C
 # files use correct "#line" directives.  Try also with the
 # 'subdir-object' option enabled.
-# See also sister test 'lex-line.test'.
+# See also sister test 'lex-line.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yacc-nodist.sh b/t/yacc-nodist.sh
index 53d9bb675..2e9c7e86b 100755
--- a/t/yacc-nodist.sh
+++ b/t/yacc-nodist.sh
@@ -15,9 +15,9 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Checks for .c and .h files derived from non-distributed yacc sources.
-# The test 'yacc-pr204.test' does similar check with AM_MAINTAINER_MODE
+# The test 'yacc-pr204.sh' does similar check with AM_MAINTAINER_MODE
 # enabled.
-# The tests 'lex-nodist.test' and 'lex-pr204.test' does similar checks
+# The tests 'lex-nodist.sh' and 'lex-pr204.sh' does similar checks
 # for lex-generated .c files.
 
 required='cc yacc'
diff --git a/t/yacc-pr204.sh b/t/yacc-pr204.sh
index 44b73b32b..babd2c9d7 100755
--- a/t/yacc-pr204.sh
+++ b/t/yacc-pr204.sh
@@ -16,8 +16,8 @@
 
 # For PR 204.
 # C sources derived from nodist_ yacc sources should not be distributed.
-# See also related test 'yacc-nodist.test'.
-# The tests 'lex-nodist.test' and 'lex-pr204.test' does similar checks
+# See also related test 'yacc-nodist.sh'.
+# The tests 'lex-nodist.sh' and 'lex-pr204.sh' does similar checks
 # for lex-generated C files.
 
 required='cc yacc'
diff --git a/t/yacc2.sh b/t/yacc2.sh
index 11a1bcbe7..64e542121 100755
--- a/t/yacc2.sh
+++ b/t/yacc2.sh
@@ -16,7 +16,7 @@
 
 # Test to make sure intermediate .h file is not generated nor removed
 # if (AM_)?YFLAGS do not contain -d.  Requested by Jim Meyering.
-# See also the related semantic test 'yacc-d-basic.test'.
+# See also the related semantic test 'yacc-d-basic.sh'.
 
 . ./defs || exit 1
 
diff --git a/t/yaccpp.sh b/t/yaccpp.sh
index 2395b561a..30ad7bcad 100755
--- a/t/yaccpp.sh
+++ b/t/yaccpp.sh
@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # Test to make sure Yacc + C++ is not obviously broken.
-# See also related tests 'yacc-cxx.test' and 'yacc-d-cxx.test',
+# See also related tests 'yacc-cxx.sh' and 'yacc-d-cxx.sh',
 # which does much more in-depth checks (but requires an actual
 # Yacc program and a working C++ compiler).
 
diff --git a/t/yaccvpath.sh b/t/yaccvpath.sh
index aacaddaf0..e56ca8e4d 100755
--- a/t/yaccvpath.sh
+++ b/t/yaccvpath.sh
@@ -20,7 +20,7 @@
 # 'make' and 'make distdir' and check whether the version of 'parse.c'
 # to be distributed is up to date.
 
-# Please keep this in sync with sister test 'yacc-d-vpath.test'.
+# Please keep this in sync with sister test 'yacc-d-vpath.sh'.
 
 required='cc yacc'
 . ./defs || exit 1
diff --git a/t/yflags.sh b/t/yflags.sh
index b1ba9a3e2..6a6bea7ff 100755
--- a/t/yflags.sh
+++ b/t/yflags.sh
@@ -16,8 +16,8 @@
 
 # Check that $(YFLAGS) takes precedence over both $(AM_YFLAGS) and
 # $(foo_YFLAGS).
-# Please keep this in sync with the sister tests yflags2.test, lflags.test
-# and lflags2.test.
+# Please keep this in sync with the sister tests yflags2.sh, lflags.sh
+# and lflags2.sh.
 
 . ./defs || exit 1
 
diff --git a/t/yflags2.sh b/t/yflags2.sh
index 9ceed4d9a..d9b913c65 100755
--- a/t/yflags2.sh
+++ b/t/yflags2.sh
@@ -16,8 +16,8 @@
 
 # Check that $(YFLAGS) takes precedence over both $(AM_YFLAGS) and
 # $(foo_YFLAGS).
-# Please keep this in sync with the sister tests yflags.test, lflags.test
-# and lflags2.test.
+# Please keep this in sync with the sister tests yflags.sh, lflags.sh
+# and lflags2.sh.
 
 . ./defs || exit 1