Add a wrapping function to the function mocking an output

Author: Pierre-Sassoulas

tests/unittest_modutils.py

@@ -6,6 +6,7 @@
 unit tests for module modutils (module manipulation utilities)
 """
 import email
+import logging
 import os
 import shutil
 import sys
@@ -16,6 +17,8 @@
 from xml import etree
 from xml.etree import ElementTree
 
+from pytest import CaptureFixture, LogCaptureFixture
+
 import astroid
 from astroid import modutils
 from astroid.interpreter._import import spec
@@ -71,6 +74,35 @@ def test_raise_load_module_from_name_1(self) -> None:
         )
 
 
+def test_import_dotted_library(
+    capsys: CaptureFixture,
+    caplog: LogCaptureFixture,
+) -> None:
+    caplog.set_level(logging.INFO)
+    del sys.modules["xml.etree.ElementTree"]
+    expected_out = "INFO (TEST): Welcome to cElementTree!"
+    expected_err = "WARNING (TEST): Monkey-patched version of cElementTree"
+
+    def function_with_stdout_and_stderr(expected_out, expected_err):
+        def mocked_function(*args, **kwargs):
+            print(f"{expected_out} args={args} kwargs={kwargs}")
+            print(expected_err, file=sys.stderr)
+
+        return mocked_function
+
+    with unittest.mock.patch(
+        "importlib.import_module",
+        side_effect=function_with_stdout_and_stderr(expected_out, expected_err),
+    ):
+        modutils.load_module_from_name("xml.etree.ElementTree")
+
+    out, err = capsys.readouterr()
+    assert expected_out in caplog.text
+    assert expected_err in caplog.text
+    assert not out
+    assert not err
+
+
 class GetModulePartTest(unittest.TestCase):
     """given a dotted name return the module part of the name"""