[repo logging] Add logging module

Bug: b/292704435
Change-Id: I8834591f661c75449f8be5de1c61ecd43669026d
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/380714
Tested-by: Aravind Vasudevan <aravindvasudev@google.com>
Reviewed-by: Joanna Wang <jojwang@google.com>
Commit-Queue: Aravind Vasudevan <aravindvasudev@google.com>

tests/test_repo_logging.py

@@ -0,0 +1,115 @@
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit test for repo_logging module."""
+import unittest
+from unittest.mock import MagicMock
+
+from repo_logging import RepoLogger
+
+
+class TestRepoLogger(unittest.TestCase):
+    def test_error_logs_error(self):
+        """Test if error fn outputs logs."""
+        logger = RepoLogger(__name__)
+        RepoLogger.errors[:] = []
+        result = None
+
+        def mock_handler(log):
+            nonlocal result
+            result = log.getMessage()
+
+        mock_out = MagicMock()
+        mock_out.level = 0
+        mock_out.handle = mock_handler
+        logger.addHandler(mock_out)
+
+        logger.error("We're no strangers to love")
+
+        self.assertEqual(result, "We're no strangers to love")
+
+    def test_warning_logs_error(self):
+        """Test if warning fn outputs logs."""
+        logger = RepoLogger(__name__)
+        RepoLogger.errors[:] = []
+        result = None
+
+        def mock_handler(log):
+            nonlocal result
+            result = log.getMessage()
+
+        mock_out = MagicMock()
+        mock_out.level = 0
+        mock_out.handle = mock_handler
+        logger.addHandler(mock_out)
+
+        logger.warning("You know the rules and so do I (do I)")
+
+        self.assertEqual(result, "You know the rules and so do I (do I)")
+
+    def test_error_aggregates_error_msg(self):
+        """Test if error fn aggregates error logs."""
+        logger = RepoLogger(__name__)
+        RepoLogger.errors[:] = []
+
+        logger.error("A full commitment's what I'm thinking of")
+        logger.error("You wouldn't get this from any other guy")
+        logger.error("I just wanna tell you how I'm feeling")
+        logger.error("Gotta make you understand")
+
+        self.assertEqual(
+            RepoLogger.errors[:],
+            [
+                "A full commitment's what I'm thinking of",
+                "You wouldn't get this from any other guy",
+                "I just wanna tell you how I'm feeling",
+                "Gotta make you understand",
+            ],
+        )
+
+    def test_log_aggregated_errors_logs_aggregated_errors(self):
+        """Test if log_aggregated_errors outputs aggregated errors."""
+        logger = RepoLogger(__name__)
+        RepoLogger.errors[:] = []
+        result = []
+
+        def mock_handler(log):
+            nonlocal result
+            result.append(log.getMessage())
+
+        mock_out = MagicMock()
+        mock_out.level = 0
+        mock_out.handle = mock_handler
+        logger.addHandler(mock_out)
+
+        logger.error("Never gonna give you up")
+        logger.error("Never gonna let you down")
+        logger.error("Never gonna run around and desert you")
+        logger.log_aggregated_errors()
+
+        self.assertEqual(
+            result,
+            [
+                "Never gonna give you up",
+                "Never gonna let you down",
+                "Never gonna run around and desert you",
+                "=" * 80,
+                "Repo command failed due to following errors:",
+                (
+                    "Never gonna give you up\n"
+                    "Never gonna let you down\n"
+                    "Never gonna run around and desert you"
+                ),
+            ],
+        )