Refactor pytest plugin to not monkey patch call_runtest_hook. (#157)

A previous refactor (#74) enabled this, but I didn't notice.
Previously, flaky stored information about test reruns inside a
CallInfo subclass. call_runtest_hook was monkey patched so that
flaky could ensure that subclass was created. #74 moved that info
into the plugin, so the monkey patch was no longer doing anything
special.

However, over time, flaky's implementation diverged from pytest's.
This caused #139 and #156.

This commit removes the monkey patch, and flaky now uses pytest's
implementation, which fixes those issues and is more future proof.

HISTORY.rst

@@ -6,6 +6,9 @@ Release History
 Upcoming
 ++++++++
 
+**Bugfixes**
+- Reraise ``KeyboardInterrupt`` when running tests under pytest.
+
 
 3.6.0 (2019-06-25)
 ++++++++++++++++++

flaky/flaky_pytest_plugin.py

@@ -2,7 +2,7 @@
 
 from __future__ import unicode_literals
 
-from _pytest.runner import CallInfo  # pylint:disable=import-error
+from _pytest.runner import call_runtest_hook  # pylint:disable=import-error
 
 from flaky._flaky_plugin import _FlakyPlugin
 from flaky.utils import ensure_unicode_string
@@ -126,7 +126,8 @@ def call_and_report(self, item, when, log=True, **kwds):
         :type log:
             `bool`
         """
-        call = self.call_runtest_hook(item, when, **kwds)
+        call = call_runtest_hook(item, when, **kwds)
+        self._call_infos[item][when] = call
         hook = item.ihook
         report = hook.pytest_runtest_makereport(item=item, call=call)
         # Start flaky modifications
@@ -289,26 +290,6 @@ def _get_test_instance(item):
                 test_instance = item.parent.obj
         return test_instance
 
-    def call_runtest_hook(self, item, when, **kwds):
-        """
-        Monkey patched from the runner plugin. Responsible for running
-        the test. Had to be patched to pass additional info to the
-        CallInfo so the tests can be rerun if necessary.
-
-        :param item:
-            pytest wrapper for the test function to be run
-        :type item:
-            :class:`Function`
-        """
-        hookname = "pytest_runtest_" + when
-        ihook = getattr(item.ihook, hookname)
-        call_info = getattr(CallInfo, "from_call", CallInfo)(
-            lambda: ihook(item=item, **kwds),
-            when=when,
-        )
-        self._call_infos[item][when] = call_info
-        return call_info
-
     def add_success(self, item):
         """
         Called when a test succeeds.

test/test_pytest/test_flaky_pytest_plugin.py

@@ -5,11 +5,12 @@
 from mock import Mock, patch
 # pylint:disable=import-error
 import pytest
+from _pytest.runner import CallInfo
 # pylint:enable=import-error
 from flaky import flaky
 from flaky import _flaky_plugin
 from flaky.flaky_pytest_plugin import (
-    CallInfo,
+    call_runtest_hook,
     FlakyPlugin,
     FlakyXdist,
     PLUGIN,
@@ -54,7 +55,7 @@ def get_calls():
 
 
 @pytest.fixture(params=['instance', 'module', 'parent'])
-def flaky_test(request):
+def flaky_test(request, mock_config):
     def test_function():
         pass
     test_owner = Mock()
@@ -63,6 +64,7 @@ def test_function():
     kwargs = {request.param: test_owner}
     test = MockTestItem(**kwargs)
     setattr(test, 'owner', test_owner)
+    setattr(test, 'config', mock_config)
     return test
 
 
@@ -103,6 +105,21 @@ def runtest(self):
         pass
 
 
+class MockConfig(object):
+    def getvalue(self, key):
+        # pylint:disable=unused-argument,no-self-use
+        return False
+
+    def getoption(self, key, default):
+        # pylint:disable=unused-argument,no-self-use
+        return default
+
+
+@pytest.fixture
+def mock_config():
+    return MockConfig()
+
+
 class MockFlakyCallInfo(CallInfo):
     def __init__(self, item, when):
         # pylint:disable=super-init-not-called
@@ -226,7 +243,7 @@ def error_raising_setup_function(item):
     flaky_test.ihook = Mock()
     flaky_test.ihook.pytest_runtest_setup = error_raising_setup_function
     flaky_plugin._call_infos[flaky_test] = {}  # pylint:disable=protected-access
-    call_info = flaky_plugin.call_runtest_hook(flaky_test, 'setup')
+    call_info = call_runtest_hook(flaky_test, 'setup')
     assert flaky_test.ran_setup
     assert string_io.getvalue() == mock_io.getvalue()
     assert call_info.excinfo.type is ZeroDivisionError