bpo-39336: Allow setattr to fail on modules which aren't assignable

📜🤖 Added by blurb_it.
Move test to data folder and improve error formatting
python · DinoV · DinoV · DinoV · Jan 14, 2020 · the-knights-who-say-ni
diff --git a/Lib/importlib/_bootstrap.py b/Lib/importlib/_bootstrap.py
+        try:
+            setattr(parent_module, child, module)
+        except AttributeError:
+            msg = (f"Can't set child package '{child}' on "
-            msg = (f"Can't set child package '{child}' on "
+            msg = (f"Cannot set an attribute on {parent!r} for child module {child!r}"
diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
@@ -1339,6 +1342,39 @@ def test_circular_from_import(self):
            str(cm.exception),
        )

+    def test_unwritable_module(self):
+        package = inspect.cleandoc('''
diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
-            with open(os.path.join(os.path.dirname(path), 'x.py'), 'w+'):
-                pass
-
+        sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'data'))
diff --git a/Lib/test/test_import/__init__.py b/Lib/test/test_import/__init__.py
            finally:
-                del sys.modules['spam.x']
-
+                sys.modules['unwritable.x']