diff --git a/t/test-lib.sh b/t/test-lib.sh
index 9001ed3a64..e2e91b5b24 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -1567,6 +1567,8 @@ fi
 # Use -P to resolve symlinks in our working directory so that the cwd
 # in subprocesses like git equals our $PWD (for pathname comparisons).
 cd -P "$TRASH_DIRECTORY" || BAIL_OUT "cannot cd -P to \"$TRASH_DIRECTORY\""
+TRASH_DIRECTORY=$(pwd)
+HOME="$TRASH_DIRECTORY"
 
 start_test_output "$0"