Support patching source code (#19561)

test/registered/debug_utils/source_patcher/conftest.py

@@ -0,0 +1,66 @@
+"""Shared fixtures for source_patcher tests.
+
+The sample module is defined as an inline string and written to a temp file
+at test time, avoiding CI complaints about fixture files without test registration.
+"""
+
+import importlib.util
+import sys
+import tempfile
+from pathlib import Path
+from types import ModuleType
+
+import pytest
+
+SAMPLE_MODULE_NAME = "_source_patcher_test_fixtures.sample_module"
+
+SAMPLE_MODULE_SOURCE = '''\
+GLOBAL_VAR = "global_value"
+
+
+class HelperClass:
+    """Utility class referenced by SampleClass to test cross-class calls."""
+
+    @staticmethod
+    def format_value(value: str) -> str:
+        return f"[{value}]"
+
+
+class SampleClass:
+    def greet(self, name: str) -> str:
+        greeting = f"hello {name}"
+        return greeting
+
+    def compute(self, x: int) -> int:
+        result = x * 2 + 1
+        return result
+
+    def uses_global(self) -> str:
+        return f"value={GLOBAL_VAR}"
+
+    def uses_helper(self, value: str) -> str:
+        return HelperClass.format_value(value)
+
+
+def standalone_function(a: int, b: int) -> int:
+    return a + b
+'''
+
+
+@pytest.fixture(scope="session")
+def sample_module() -> ModuleType:
+    """Load the sample module from a temp file and register it in sys.modules."""
+    if SAMPLE_MODULE_NAME in sys.modules:
+        return sys.modules[SAMPLE_MODULE_NAME]
+
+    tmpdir = tempfile.mkdtemp(prefix="source_patcher_fixtures_")
+    module_path = Path(tmpdir) / "sample_module.py"
+    module_path.write_text(SAMPLE_MODULE_SOURCE)
+
+    spec = importlib.util.spec_from_file_location(SAMPLE_MODULE_NAME, module_path)
+    assert spec is not None
+    assert spec.loader is not None
+    module = importlib.util.module_from_spec(spec)
+    sys.modules[SAMPLE_MODULE_NAME] = module
+    spec.loader.exec_module(module)
+    return module