Context manager to disable logging

 #56

pytestqt/_tests/test_logging.py

@@ -87,6 +87,38 @@ def test_types(qtlog):
     res.stdout.fnmatch_lines('*1 passed*')
 
 
+@pytest.mark.parametrize('use_context_manager', [True, False])
+def test_disable_qtlog_context_manager(testdir, use_context_manager):
+    """
+    Test qtlog.disabled() context manager.
+
+    :type testdir: _pytest.pytester.TmpTestdir
+    """
+    testdir.makeini(
+        """
+        [pytest]
+        qt_log_level_fail = CRITICAL
+        """
+    )
+
+    if use_context_manager:
+        code = 'with qtlog.disabled():'
+    else:
+        code = 'if 1:'
+
+    testdir.makepyfile(
+        """
+        from pytestqt.qt_compat import qCritical
+        def test_1(qtlog):
+            {code}
+                qCritical('message')
+        """.format(code=code)
+    )
+    res = testdir.inline_run()
+    passed = 1 if use_context_manager else 0
+    res.assertoutcome(passed=passed, failed=int(not passed))
+
+
 def test_logging_formatting(testdir):
     """
     Test custom formatting for logging messages.

pytestqt/plugin.py

@@ -637,8 +637,7 @@ def pytest_runtest_setup(self, item):
         else:
             ignore_regexes = self.config.getini('qt_log_ignore')
         item.qt_log_capture = _QtMessageCapture(ignore_regexes)
-        previous_handler = qInstallMsgHandler(item.qt_log_capture._handle)
-        item.qt_previous_handler = previous_handler
+        item.qt_log_capture._start()
 
     @pytest.mark.hookwrapper
     def pytest_runtest_makereport(self, item, call):
@@ -682,8 +681,7 @@ def pytest_runtest_makereport(self, item, call):
                         long_repr.addsection('Captured Qt messages',
                                              '\n'.join(lines))
 
-            qInstallMsgHandler(item.qt_previous_handler)
-            del item.qt_previous_handler
+            item.qt_log_capture._stop()
             del item.qt_log_capture
 
 
@@ -700,6 +698,25 @@ class _QtMessageCapture(object):
     def __init__(self, ignore_regexes):
         self._records = []
         self._ignore_regexes = ignore_regexes or []
+        self._previous_handler = None
+
+    def _start(self):
+        self._previous_handler = qInstallMsgHandler(self._handle)
+
+    def _stop(self):
+        qInstallMsgHandler(self._previous_handler)
+
+    @contextmanager
+    def disabled(self):
+        """
+        Context manager that temporarily disables logging capture while
+        inside it.
+        """
+        self._stop()
+        try:
+            yield
+        finally:
+            self._start()
 
     _Context = namedtuple('_Context', 'file function line')