RAHHH

backend/lib/python3.12/site-packages/twisted/python/test/modules_helpers.py

@@ -0,0 +1,57 @@
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Facilities for helping test code which interacts with Python's module system
+to load code.
+"""
+
+import sys
+from types import ModuleType
+from typing import Iterable, List, Tuple
+
+from twisted.python.filepath import FilePath
+
+
+class TwistedModulesMixin:
+    """
+    A mixin for C{twisted.trial.unittest.SynchronousTestCase} providing useful
+    methods for manipulating Python's module system.
+    """
+
+    def replaceSysPath(self, sysPath: List[str]) -> None:
+        """
+        Replace sys.path, for the duration of the test, with the given value.
+        """
+        originalSysPath = sys.path[:]
+
+        def cleanUpSysPath() -> None:
+            sys.path[:] = originalSysPath
+
+        self.addCleanup(cleanUpSysPath)  # type: ignore[attr-defined]
+        sys.path[:] = sysPath
+
+    def replaceSysModules(self, sysModules: Iterable[Tuple[str, ModuleType]]) -> None:
+        """
+        Replace sys.modules, for the duration of the test, with the given value.
+        """
+        originalSysModules = sys.modules.copy()
+
+        def cleanUpSysModules() -> None:
+            sys.modules.clear()
+            sys.modules.update(originalSysModules)
+
+        self.addCleanup(cleanUpSysModules)  # type: ignore[attr-defined]
+        sys.modules.clear()
+        sys.modules.update(sysModules)
+
+    def pathEntryWithOnePackage(self, pkgname: str = "test_package") -> FilePath[str]:
+        """
+        Generate a L{FilePath} with one package, named C{pkgname}, on it, and
+        return the L{FilePath} of the path entry.
+        """
+        entry = FilePath(self.mktemp())  # type: ignore[attr-defined]
+        pkg = entry.child("test_package")
+        pkg.makedirs()
+        pkg.child("__init__.py").setContent(b"")
+        return entry