patch 8.0.1832: cannot use :unlet for an environment variablev8.0.1832

Problem:    Cannot use :unlet for an environment variable.
Solution:   Make it work.  Use unsetenv() if available. (Ken Takata,
            closes #2855)

1 files changed, 24 insertions, 0 deletions

diff --git a/src/testdir/test_unlet.vim b/src/testdir/test_unlet.vim
index c20b0beb7..6636f6d66 100644
--- a/src/testdir/test_unlet.vim
+++ b/src/testdir/test_unlet.vim
@@ -21,3 +21,27 @@ endfunc
 func Test_unlet_fails()
   call assert_fails('unlet v:["count"]', 'E46:')
 endfunc
+
+func Test_unlet_env()
+  let envcmd = has('win32') ? 'set' : 'env'
+
+  let $FOOBAR = 'test'
+  let found = 0
+  for kv in split(system(envcmd), "\r*\n")
+    if kv == 'FOOBAR=test'
+      let found = 1
+    endif
+  endfor
+  call assert_equal(1, found)
+
+  unlet $FOOBAR
+  let found = 0
+  for kv in split(system(envcmd), "\r*\n")
+    if kv == 'FOOBAR=test'
+      let found = 1
+    endif
+  endfor
+  call assert_equal(0, found)
+
+  unlet $MUST_NOT_BE_AN_ERROR
+endfunc