Test Coverage for older django versions (#24968)

Related to this issue:
#24199

@mcobalchinisoftfocus Discovered an issue with older django versions,
which didn't have the main function in the manage.py


#24927 (comment)

I've fixed this issue by executing the code in manage.py with __name__
set to __main__ instead of relying on main function being there.

I've also adjusted the test, so that it would cover this case.

Author: danila-grobov

python_files/tests/unittestadapter/.data/simple_django/old_manage.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+import os
+import sys
+if __name__ == "__main__":
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'mysite.settings')
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError:
+        # The above import may fail for some other reason. Ensure that the
+        # issue is really that Django is missing to avoid masking other
+        # exceptions on Python 2.
+        try:
+            import django
+        except ImportError:
+            raise ImportError(
+                "Couldn't import Django. Are you sure it's installed and "
+                "available on your PYTHONPATH environment variable? Did you "
+                "forget to activate a virtual environment?"
+            )
+        raise
+    execute_from_command_line(sys.argv)

python_files/tests/unittestadapter/test_coverage.py

@@ -53,11 +53,12 @@ def test_basic_coverage():
     assert set(focal_function_coverage.get("lines_missed")) == {6}
 
 
+@pytest.mark.parametrize("manage_py_file", ["manage.py", "old_manage.py"])
 @pytest.mark.timeout(30)
-def test_basic_django_coverage():
+def test_basic_django_coverage(manage_py_file):
     """This test validates that the coverage is correctly calculated for a Django project."""
     data_path: pathlib.Path = TEST_DATA_PATH / "simple_django"
-    manage_py_path: str = os.fsdecode(data_path / "manage.py")
+    manage_py_path: str = os.fsdecode(data_path / manage_py_file)
     execution_script: pathlib.Path = python_files_path / "unittestadapter" / "execution.py"
 
     test_ids = [
@@ -82,7 +83,7 @@ def test_basic_django_coverage():
     assert coverage
     results = coverage["result"]
     assert results
-    assert len(results) == 15
+    assert len(results) == 16
     polls_views_coverage = results.get(str(data_path / "polls" / "views.py"))
     assert polls_views_coverage
     assert polls_views_coverage.get("lines_covered") is not None

python_files/unittestadapter/django_handler.py

@@ -1,17 +1,12 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License.
 
-import importlib.util
 import os
 import pathlib
 import subprocess
 import sys
 from contextlib import contextmanager, suppress
-from typing import TYPE_CHECKING, Generator, List
-
-if TYPE_CHECKING:
-    from importlib.machinery import ModuleSpec
-
+from typing import Generator, List
 
 script_dir = pathlib.Path(__file__).parent
 sys.path.append(os.fspath(script_dir))
@@ -75,8 +70,9 @@ def django_discovery_runner(manage_py_path: str, args: List[str]) -> None:
 
 
 def django_execution_runner(manage_py_path: str, test_ids: List[str], args: List[str]) -> None:
+    manage_path: pathlib.Path = pathlib.Path(manage_py_path)
     # Attempt a small amount of validation on the manage.py path.
-    if not pathlib.Path(manage_py_path).exists():
+    if not manage_path.exists():
         raise VSCodeUnittestError("Error running Django, manage.py path does not exist.")
 
     try:
@@ -89,28 +85,27 @@ def django_execution_runner(manage_py_path: str, test_ids: List[str], args: List
         else:
             env["PYTHONPATH"] = os.fspath(custom_test_runner_dir)
 
-        django_project_dir: pathlib.Path = pathlib.Path(manage_py_path).parent
+        django_project_dir: pathlib.Path = manage_path.parent
         sys.path.insert(0, os.fspath(django_project_dir))
         print(f"Django project directory: {django_project_dir}")
 
-        manage_spec: ModuleSpec | None = importlib.util.spec_from_file_location(
-            "manage", manage_py_path
-        )
-        if manage_spec is None or manage_spec.loader is None:
-            raise VSCodeUnittestError("Error importing manage.py when running Django testing.")
-        manage_module = importlib.util.module_from_spec(manage_spec)
-        manage_spec.loader.exec_module(manage_module)
-
         manage_argv: List[str] = [
-            manage_py_path,
+            str(manage_path),
             "test",
             "--testrunner=django_test_runner.CustomExecutionTestRunner",
             *args,
             *test_ids,
         ]
         print(f"Django manage.py arguments: {manage_argv}")
 
-        with override_argv(manage_argv), suppress(SystemExit):
-            manage_module.main()
+        try:
+            argv_context = override_argv(manage_argv)
+            suppress_context = suppress(SystemExit)
+            manage_file = manage_path.open()
+            with argv_context, suppress_context, manage_file:
+                manage_code = manage_file.read()
+                exec(manage_code, {"__name__": "__main__"})
+        except OSError as e:
+            raise VSCodeUnittestError("Error running Django, unable to read manage.py") from e
     except Exception as e:
         print(f"Error during Django test execution: {e}", file=sys.stderr)