fix(cli): cfn test broken on Windows - NamedTemporaryFile issue (#924)

* Work around to temporary_ini_file to work on Windows

* Fix formating and unit tests

* Explicitly close file in temporary_ini_file and catch FileNotFoundError exceptions

Author: mmaeng

src/rpdk/core/test.py

@@ -77,14 +77,27 @@ def empty_hook_override():
     return {"CREATE_PRE_PROVISION": {}}
 
 
+# As per Python docs NamedTemporaryFile does NOT work the same in Windows.  Setting delete=False as workaround.
+#
+# Temporary file must be explicitly cleaned up after temporary_ini_file() is called!
+#
+# "Whether the name can be used to open the file a second time, while the named temporary file is still open,
+# varies across platforms (it can be so used on Unix; it cannot on Windows)."
+# https://docs.python.org/3.9/library/tempfile.html#tempfile.NamedTemporaryFile
+#
+# Fix being tracked here https://github.com/python/cpython/issues/58451
+
+
 @contextmanager
 def temporary_ini_file():
     with NamedTemporaryFile(
-        mode="w", encoding="utf-8", prefix="pytest_", suffix=".ini"
+        mode="w", encoding="utf-8", prefix="pytest_", suffix=".ini", delete=False
     ) as temp:
         LOG.debug("temporary pytest.ini path: %s", temp.name)
         path = Path(temp.name).resolve(strict=True)
         copy_resource(__name__, "data/pytest-contract.ini", path)
+        # Close temporary file for other processes to use, needed on Windows
+        temp.close()
         yield str(path)
 
 
@@ -394,6 +407,11 @@ def invoke_test(args, project, overrides, inputs):
             pytest_args.extend(args.passed_to_pytest)
         LOG.debug("pytest args: %s", pytest_args)
         ret = pytest.main(pytest_args, plugins=[plugin])
+        # Manually clean up temporary file before exiting - issue with NamedTemporaryFile method on Windows
+        try:
+            os.unlink(path)
+        except FileNotFoundError:
+            pass
         if ret:
             raise SysExitRecommendedError("One or more contract tests failed")
 

tests/test_test.py

@@ -337,6 +337,11 @@ def test_temporary_ini_file():
 
         with path.open("r", encoding="utf-8") as f:
             assert "[pytest]" in f.read()
+        # Manually clean up temporary file before exiting - issue with NamedTemporaryFile method on Windows
+        try:
+            os.unlink(path_str)
+        except FileNotFoundError:
+            pass
 
 
 def test_get_overrides_no_root():