tests: reenable the surrogate-pair test

This reverts commit bdb98cec2e7bf255e1d00eaf8be16299f7bf571e,
but adding the comment changes suggested by Bruno Haible in
https://lists.gnu.org/r/grep-devel/2018-12/msg00037.html
* tests/surrogate-pair: New file.
* tests/Makefile.am (TESTS): List it.

2 files changed, 45 insertions, 0 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 872024f5..a7e8f271 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -153,6 +153,7 @@ TESTS =						\
   spencer1-locale				\
   stack-overflow				\
   status					\
+  surrogate-pair				\
   symlink					\
   triple-backref				\
   turkish-I					\
diff --git a/tests/surrogate-pair b/tests/surrogate-pair
new file mode 100755
index 00000000..34e569bb
--- /dev/null
+++ b/tests/surrogate-pair
@@ -0,0 +1,44 @@
+#!/bin/sh
+# Check the handling of characters outside the Unicode BMP.
+# Known failures: This test currently fails on Cygwin and AIX.
+
+# Copyright (C) 2013-2018 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 3 of the License, 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 <https://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+
+require_en_utf8_locale_
+require_compiled_in_MB_support
+
+fail=0
+
+printf '\360\220\220\205\n' > in || framework_failure_
+
+LC_ALL=en_US.UTF-8
+export LC_ALL
+
+# On Cygwin, before grep-2.15, this would segfault.
+# Require not just non-zero exit status, but exactly 1.
+returns_ 1 grep -i anything-else in > out 2>&1 || fail=1
+# Expect no output.
+compare /dev/null out || fail=1
+
+# Also test whether a surrogate-pair in the search string works.
+for opt in '' -i -E -F -iE -iF; do
+  grep --file=in $opt in > out 2>&1 || fail=1
+  compare out in || fail=1
+done
+
+Exit $fail