logfail: Continue running test and fail afterwards.

tests/helpers/logfail.py

@@ -40,6 +40,7 @@ class LogFailHandler(logging.Handler):
 
     def __init__(self, level=logging.NOTSET, min_level=logging.WARNING):
         self._min_level = min_level
+        self.failed = False
         super().__init__(level)
 
     def emit(self, record):
@@ -62,9 +63,7 @@ class LogFailHandler(logging.Handler):
             return
         if record.levelno < self._min_level:
             return
-        pytest.fail("Got logging message on logger {} with level {}: "
+        self.failed = True
-                    "{}!".format(record.name, record.levelname,
-                                 record.getMessage()))
 
 
 @pytest.yield_fixture(scope='session', autouse=True)
@@ -74,6 +73,8 @@ def fail_on_logging():
     yield
     logging.getLogger().removeHandler(handler)
     handler.close()
+    if handler.failed:
+        pytest.fail("Got unexpected logging message!", pytrace=False)
 
 
 @pytest.yield_fixture(autouse=True)

tests/helpers/test_logfail.py

@@ -127,6 +127,48 @@ def test_log_expected_wrong_logger(log_testdir):
     res.stdout.fnmatch_lines(['*1 error*'])
 
 
+def test_output_passing(log_testdir):
+    log_testdir.makepyfile("""
+        import logging
+
+        def test_foo():
+            logging.error('log msg 1')
+            logging.error('log msg 2')
+    """)
+    res = log_testdir.runpytest('-p capturelog')
+    res.stdout.fnmatch_lines([
+        '*= ERRORS =*',
+        '*_ ERROR at teardown of test_foo _*',
+        'Got unexpected logging message!',
+
+        '*1 error*',
+    ])
+
+
+def test_output_failing(log_testdir):
+    log_testdir.makepyfile("""
+        import logging
+
+        def test_foo():
+            logging.error('log msg 1')
+            logging.error('log msg 2')
+            raise Exception
+    """)
+    res = log_testdir.runpytest('-p capturelog')
+    res.stdout.fnmatch_lines([
+        '*= ERRORS =*',
+        '*_ ERROR at teardown of test_foo _*',
+        'Got unexpected logging message!',
+
+        '*= FAILURES =*',
+        '*- Captured log -*',
+        '*ERROR    log msg 1',
+        '*ERROR    log msg 2',
+
+        '*1 error*',
+    ])
+
+
 @pytest.fixture
 def skipping_fixture():
     pytest.skip("Skipping to test caplog workaround.")