test(assert_complete): support systems with OLDPWD being unset

Author: akinomyoga

test/t/conftest.py

@@ -499,7 +499,7 @@ def assert_complete(
     if cwd:
         assert_bash_exec(
             bash,
-            "_bash_completion_test_OLDPWD=$OLDPWD;cd %s"
+            "[[ ! ${OLDPWD+set} ]] || _bash_completion_test_OLDPWD=$OLDPWD;cd %s"
             % shlex.quote(str(cwd)),
             want_output=None,
         )
@@ -567,7 +567,7 @@ def assert_complete(
         if cwd:
             assert_bash_exec(
                 bash,
-                "cd -;OLDPWD=$_bash_completion_test_OLDPWD",
+                "cd -;if [[ ${_bash_completion_test_OLDPWD+set} ]]; then OLDPWD=$_bash_completion_test_OLDPWD; else unset -v OLDPWD; fi",
                 want_output=None,
             )
     return result