Merge pull request #17641 from ericgribkoff/logging_test_fix

Do not reload grpc in unit tests

src/python/grpcio_tests/tests/unit/_logging_test.py

@@ -14,66 +14,86 @@
 """Test of gRPC Python's interaction with the python logging module"""
 
 import unittest
-import six
-from six.moves import reload_module
 import logging
 import grpc
-import functools
+import subprocess
 import sys
 
+INTERPRETER = sys.executable
 
-def patch_stderr(f):
 
-    @functools.wraps(f)
-    def _impl(*args, **kwargs):
-        old_stderr = sys.stderr
-        sys.stderr = six.StringIO()
-        try:
-            f(*args, **kwargs)
-        finally:
-            sys.stderr = old_stderr
+class LoggingTest(unittest.TestCase):
 
-    return _impl
+    def test_logger_not_occupied(self):
+        script = """if True:
+            import logging
 
+            import grpc
 
-def isolated_logging(f):
+            if len(logging.getLogger().handlers) != 0:
+                raise Exception('expected 0 logging handlers')
 
-    @functools.wraps(f)
-    def _impl(*args, **kwargs):
-        reload_module(logging)
-        reload_module(grpc)
-        try:
-            f(*args, **kwargs)
-        finally:
-            reload_module(logging)
+        """
+        self._verifyScriptSucceeds(script)
 
-    return _impl
+    def test_handler_found(self):
+        script = """if True:
+            import logging
 
+            import grpc
+        """
+        out, err = self._verifyScriptSucceeds(script)
+        self.assertEqual(0, len(err), 'unexpected output to stderr')
 
-class LoggingTest(unittest.TestCase):
+    def test_can_configure_logger(self):
+        script = """if True:
+            import logging
+            import six
 
-    @isolated_logging
-    def test_logger_not_occupied(self):
-        self.assertEqual(0, len(logging.getLogger().handlers))
+            import grpc
 
-    @patch_stderr
-    @isolated_logging
-    def test_handler_found(self):
-        self.assertEqual(0, len(sys.stderr.getvalue()))
 
-    @isolated_logging
-    def test_can_configure_logger(self):
-        intended_stream = six.StringIO()
-        logging.basicConfig(stream=intended_stream)
-        self.assertEqual(1, len(logging.getLogger().handlers))
-        self.assertIs(logging.getLogger().handlers[0].stream, intended_stream)
+            intended_stream = six.StringIO()
+            logging.basicConfig(stream=intended_stream)
+
+            if len(logging.getLogger().handlers) != 1:
+                raise Exception('expected 1 logging handler')
+
+            if logging.getLogger().handlers[0].stream is not intended_stream:
+                raise Exception('wrong handler stream')
+
+        """
+        self._verifyScriptSucceeds(script)
 
-    @isolated_logging
     def test_grpc_logger(self):
-        self.assertIn("grpc", logging.Logger.manager.loggerDict)
-        root_logger = logging.getLogger("grpc")
-        self.assertEqual(1, len(root_logger.handlers))
-        self.assertIsInstance(root_logger.handlers[0], logging.NullHandler)
+        script = """if True:
+            import logging
+
+            import grpc
+
+            if "grpc" not in logging.Logger.manager.loggerDict:
+                raise Exception('grpc logger not found')
+
+            root_logger = logging.getLogger("grpc")
+            if len(root_logger.handlers) != 1:
+                raise Exception('expected 1 root logger handler')
+            if not isinstance(root_logger.handlers[0], logging.NullHandler):
+                raise Exception('expected logging.NullHandler')
+
+        """
+        self._verifyScriptSucceeds(script)
+
+    def _verifyScriptSucceeds(self, script):
+        process = subprocess.Popen(
+            [INTERPRETER, '-c', script],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE)
+        out, err = process.communicate()
+        self.assertEqual(
+            0, process.returncode,
+            'process failed with exit code %d (stdout: %s, stderr: %s)' %
+            (process.returncode, out, err))
+        return out, err
 
 
 if __name__ == '__main__':