Add captured log lines to test case details.

Change-Id: I9615842c9b36dab11aed6561a76cf721c03a6a62

tobiko/common/_logging.py

@@ -0,0 +1,87 @@
+# Copyright 2019 Red Hat
+#
+#    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.
+from __future__ import absolute_import
+
+import logging
+
+from oslo_log import log
+
+import testtools
+from testtools import content
+
+from tobiko.common import _fixture
+
+
+LOG = log.getLogger(__name__)
+
+
+class CaptureLogFixture(_fixture.SharedFixture):
+
+    level = None
+    logger = logging.root
+    handler = None
+
+    def __init__(self, logger=None, level=None):
+        super(CaptureLogFixture, self).__init__()
+        if logger:
+            self.logger = logger
+        if level:
+            self.level = level
+
+    def setup_fixture(self):
+        self.handler = handler = CaptureLogHandler(level=self.level)
+        self.logger.addHandler(handler)
+        self.addCleanup(self.logger.removeHandler, handler)
+
+    def getDetails(self):
+        if self.handler:
+            return {'log': self.handler.content}
+        else:
+            return {}
+
+
+class CaptureLogHandler(logging.Handler):
+
+    def __init__(self, level=None):
+        if level is None:
+            from tobiko import config
+            CONF = config.CONF
+            if CONF.tobiko.debug:
+                level = logging.DEBUG
+            else:
+                level = logging.INFO
+        super(CaptureLogHandler, self).__init__(level)
+        self.records = []
+
+    def emit(self, record):
+        self.records.append(record)
+
+    @property
+    def content(self):
+        return content.Content(content.UTF8_TEXT, self.format_all)
+
+    def format_all(self):
+        for record in self.records:
+            yield (self.format(record) + '\n').encode()
+
+
+class CaptureLogTest(testtools.TestCase):
+
+    capture_log_level = logging.DEBUG
+    capture_log_logger = logging.root
+
+    def setUp(self):
+        self.useFixture(CaptureLogFixture(level=self.capture_log_level,
+                                          logger=self.capture_log_logger))
+        super(CaptureLogTest, self).setUp()