--- a/tests/test-rhg.t	Wed Nov 24 20:51:01 2021 -0500
+++ b/tests/test-rhg.t	Thu Nov 11 14:26:25 2021 +0000
@@ -168,13 +168,12 @@
   $ rhg cat original --exclude="*.rs"
   original content
 
-  $ FALLBACK_EXE="$RHG_FALLBACK_EXECUTABLE"
-  $ unset RHG_FALLBACK_EXECUTABLE
-  $ rhg cat original --exclude="*.rs"
+  $ (unset RHG_FALLBACK_EXECUTABLE; rhg cat original --exclude="*.rs")
   abort: 'rhg.on-unsupported=fallback' without 'rhg.fallback-executable' set.
   [255]
-  $ RHG_FALLBACK_EXECUTABLE="$FALLBACK_EXE"
-  $ export RHG_FALLBACK_EXECUTABLE
+
+  $ (unset RHG_FALLBACK_EXECUTABLE; rhg cat original)
+  original content
 
   $ rhg cat original --exclude="*.rs" --config rhg.fallback-executable=false
   [1]