diff --git a/src/testdir/vim9.vim b/src/testdir/vim9.vim
index 782809b..764b611 100644
--- a/src/testdir/vim9.vim
+++ b/src/testdir/vim9.vim
@@ -112,11 +112,13 @@
 
 # :source a list of "lines" and check whether it fails with "error"
 export def CheckSourceFailure(lines: list<string>, error: string, lnum = -3)
+  var cwd = getcwd()
   new
   setline(1, lines)
   try
     assert_fails('source', error, lines, lnum)
   finally
+    chdir(cwd)
     bw!
   endtry
 enddef
@@ -124,22 +126,26 @@
 # :source a list of "lines" and check whether it fails with the list of
 # "errors"
 export def CheckSourceFailureList(lines: list<string>, errors: list<string>, lnum = -3)
+  var cwd = getcwd()
   new
   setline(1, lines)
   try
     assert_fails('source', errors, lines, lnum)
   finally
+    chdir(cwd)
     bw!
   endtry
 enddef
 
 # :source a list of "lines" and check whether it succeeds
 export def CheckSourceSuccess(lines: list<string>)
+  var cwd = getcwd()
   new
   setline(1, lines)
   try
     :source
   finally
+    chdir(cwd)
     bw!
   endtry
 enddef