Create the harness and shell of update_test_expectations

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/update_test_expectations_unittest.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/update_test_expectations_unittest.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/update_test_expectations_unittest.py b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/update_test_expectations_unittest.py
new file mode 100644
index 0000000000000000000000000000000000000000..655d6a4b9301680fc5f4afe50bfdf8ab05df3e02
--- /dev/null
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/update_test_expectations_unittest.py
@@ -0,0 +1,330 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import logging
+import unittest
+import StringIO
+from collections import OrderedDict

[qyearsley, 2016/07/08 00:06:21]

Nit: In most of the files, there's a blank line between the standard library
imports and the webkitpy imports.

[bokan, 2016/07/08 14:29:49]

Done.

+from webkitpy.common.host_mock import MockHost
+from webkitpy.common.system.filesystem_mock import MockFileSystem
+from webkitpy.layout_tests.builder_list import BuilderList
+from webkitpy.layout_tests.port.factory import PortFactory
+from webkitpy.layout_tests.port.test import LAYOUT_TEST_DIR
+from webkitpy.layout_tests.update_test_expectations import main
+from webkitpy.layout_tests.update_test_expectations import RemoveFlakesOMatic
+
+logger = logging.getLogger()
+logger.level = logging.DEBUG
+
+
+class FakeBotTestExpectations(object):
+
+    def __init__(self, results_by_path):
+        self._results = results_by_path
+
+    def all_results_by_path(self):
+        return self._results
+
+
+class FakeBotTestExpectationsFactory(object):
+
+    def __init__(self):
+        """
+        The distinct results seen in at least one run of the test.
+        E.g. if the bot results for mytest.html are:
+            PASS PASS FAIL PASS TIMEOUT
+        then _all_results_by_builder would be:
+            {
+                'WebKit Linux' : {
+                    'mytest.html': ['FAIL', 'PASS', 'TIMEOUT']
+                }
+            }
+        """
+        self._all_results_by_builder = {}
+
+    def expectations_for_builder(self, builder):
+        if builder not in self._all_results_by_builder:
+            return None
+
+        return FakeBotTestExpectations(self._all_results_by_builder[builder])
+
+
+class FakePortFactory(PortFactory):
+
+    def __init__(self, host):
+        super(FakePortFactory, self).__init__(host)
+        self._all_build_types = ()
+        self._all_systems = ()
+        self._configuration_specifier_macros = {
+            'mac': ['mac10.10'],
+            'win': ['win7'],
+            'linux': ['precise']
+        }
+
+    def get(self, port_name=None, options=None, **kwargs):
+        """Returns an object implementing the Port interface. This
+        fake object will always return the 'test' port factory."""

[qyearsley, 2016/07/08 00:06:21]

I personally think that docstrings with a one-line summary sentence, then a
blank line, then details are the easiest to scan, e.g.

"""Returns an object implementing the Port interface.

This fake object will always return the 'test' port factory.
"""

[bokan, 2016/07/08 14:29:49]

Done.

+        port = super(FakePortFactory, self).get('test', None)
+        port._all_build_types = self._all_build_types
+        port._all_systems = self._all_systems
+        port._configuration_specifier_macros = (
+            self._configuration_specifier_macros)

[Dirk Pranke, 2016/07/06 21:51:44]

as suggested in the earlier CL, update these names to refer to public instance
variables, e.g., port.all_build_systems = ...

[bokan, 2016/07/07 22:08:32]

Done.

+        return port
+
+
+class UpdateTestExpectationsTest(unittest.TestCase):
+
+    def setUp(self):
+        self._host = MockHost()
+        self._port = self._host.port_factory.get('test', None)
+        self._expectation_factory = FakeBotTestExpectationsFactory()
+        self._flake_remover = RemoveFlakesOMatic(self._host,
+                                                 self._port,
+                                                 self._expectation_factory)
+        self._port._configuration_specifier_macros = {
+            'mac': ['mac10.10'],
+            'win': ['win7'],
+            'linux': ['precise']
+        }
+        filesystem = self._host.filesystem
+        self._write_tests_into_filesystem(filesystem)
+
+        self._log_output = StringIO.StringIO()
+        self._stream_handler = logging.StreamHandler(self._log_output)
+        logger.addHandler(self._stream_handler)
+
+    def tearDown(self):
+        logger.removeHandler(self._stream_handler)
+        self._log_output.close()
+
+    def _write_tests_into_filesystem(self, filesystem):
+        test_list = ['test/a.html',
+                     'test/b.html',
+                     'test/c.html',
+                     'test/d.html',
+                     'test/e.html',
+                     'test/f.html',
+                     'test/g.html']
+        for test in test_list:
+            path = filesystem.join(LAYOUT_TEST_DIR, test)
+            filesystem.write_binary_file(path, '')
+
+    def _assert_expectations_match(self, expectations, expected_string):
+        self.assertIsNotNone(expectations)
+        stringified_expectations = "\n".join(
+            x.to_string(None) for x in expectations)

[qyearsley, 2016/07/06 23:18:04]

Note: I wonder if it would be nice to change TestExpectationLine.to_string so
that the argument `test_configuration_converter` is optional and has a default
value of None. Then, this mysterious None wouldn't have to be passed in here.
But this is separate from this CL.

[bokan, 2016/07/07 22:08:32]

It turns out this is the only use of TestExpectationLine.to_string that uses all
defaults so I went ahead and made None the default for the converter in this
patch.

+        expected_string = "\n".join(
+            x.strip() for x in expected_string.split("\n"))
+        self.assertEqual(stringified_expectations, expected_string)
+
+    def _parse_expectations(self, expectations):
+        """Parses a TestExpectation file given as string.
+
+        This function takes a string representing the contents of the
+        TestExpectations file and parses it, producing the TestExpectations
+        object and sets it on the Port object where the script will read it
+        from.
+
+        Args:
+            expectations: A string containing the contents of the
+            TestExpectations file to use.
+        """
+        expectations_dict = OrderedDict()
+        expectations_dict['expectations'] = expectations
+        self._port.expectations_dict = lambda: expectations_dict
+
+    def _define_builders(self, builders_dict):
+        """Defines the available builders for the test.
+
+        Args:
+            builders_dict: A dictionary containing builder names to their
+            attributes, see BuilderList.__init__ for the format.
+        """
+        self._host.builders = BuilderList(builders_dict)
+
+    def test_dont_remove_non_flakes(self):
+        """Tests that lines that aren't flaky are not touched.
+
+        Lines are flaky if they contain a PASS as well as at least one other
+        failing result.
+        """
+        test_expectations_before = """
+            # Even though the results show all passing, none of the
+            # expectations are flaky so we shouldn't remove any.
+            Bug(test) test/a.html [ Pass ]
+            Bug(test) test/b.html [ Timeout ]
+            Bug(test) test/c.html [ Failure Timeout ]
+            Bug(test) test/d.html [ Rebaseline ]
+            Bug(test) test/e.html [ NeedsManualRebaseline ]
+            Bug(test) test/f.html [ NeedsRebaseline ]"""
+
+        self._define_builders({
+            "WebKit Linux": {
+                "port_name": "linux-precise",
+                "specifiers": ['Precise', 'Release']
+            },
+        })
+        self._port._all_build_types = ('release',)
+        self._port._all_systems = (('precise', 'x86_64'),)
+
+        self._parse_expectations(test_expectations_before)
+        self._expectation_factory._all_results_by_builder = {
+            'WebKit Linux': {
+                "test/a.html": ["PASS", "PASS"],
+                "test/b.html": ["PASS", "PASS"],
+                "test/c.html": ["PASS", "PASS"],
+                "test/d.html": ["PASS", "PASS"],
+                "test/e.html": ["PASS", "PASS"],
+                "test/f.html": ["PASS", "PASS"],
+            }
+        }
+        updated_expectations = (
+            self._flake_remover.get_updated_test_expectations())
+        self._assert_expectations_match(
+            updated_expectations, test_expectations_before)
+
+    def test_dont_remove_skip(self):
+        """Tests that lines with Skip are untouched.
+
+        If a line is marked as Skip, it will eventually contain no results,
+        which is indistinguishable from "All Passing" so don't remove since we
+        don't know what the results actually are.
+        """
+        test_expectations_before = """
+            # Skip expectations should never be removed.
+            Bug(test) test/a.html [ Skip ]
+            Bug(test) test/b.html [ Skip ]
+            Bug(test) test/c.html [ Skip ]"""
+
+        self._define_builders({
+            "WebKit Linux": {
+                "port_name": "linux-precise",
+                "specifiers": ['Precise', 'Release']
+            },
+        })
+        self._port._all_build_types = ('release',)
+        self._port._all_systems = (('precise', 'x86_64'),)
+
+        self._parse_expectations(test_expectations_before)
+        self._expectation_factory._all_results_by_builder = {
+            'WebKit Linux': {
+                "test/a.html": ["PASS", "PASS"],
+                "test/b.html": ["PASS", "IMAGE"],
+            }
+        }
+        updated_expectations = (
+            self._flake_remover.get_updated_test_expectations())
+        self._assert_expectations_match(
+            updated_expectations, test_expectations_before)
+
+    def test_dont_remove_rebaselines(self):
+        """Tests that lines with rebaseline expectations are untouched.
+        """

[qyearsley, 2016/07/06 23:18:04]

Nit: end quote can go on the line above.

[bokan, 2016/07/07 22:08:32]

Done. Does this go for multiline comments too or just the single lines?

Is there a python style guide we use? Is it just the Google Python SG?

[qyearsley, 2016/07/08 00:06:21]

The Python style guide for Blink just say to use PEP8 (see
https://www.chromium.org/blink/coding-style#TOC-Python,
https://www.python.org/dev/peps/pep-0008/). The relevant section in PEP8 is:
https://www.python.org/dev/peps/pep-0008/#documentation-strings

[bokan, 2016/07/08 14:29:49]

Thanks!

+        test_expectations_before = """
+            # Even though the results show all passing, none of the

[qyearsley, 2016/07/08 00:06:21]

I assume it's not a problem that these lines start with whitespace?

If you wanted to make a multi-line string where the lines don't start with space
and the formatting is still nice like this, you can use the fact that adjacent
strings are concatenated in Python, e.g.:

test_expectations_before = (
    '# Even though the results show all passing, none of the\n'
    '# expectations are flaky so we shouldn't remove any.\n'
    'Bug(test) test/a.html [ Failure NeedsRebaseline Pass ]\n')

[bokan, 2016/07/08 14:29:49]

I think this is easier to read and the assert_expectations_match method ignores
surrounding white space so it doesn't matter in these cases. Also,
TestExpectations can start with a blank so it's a valid file.

+            # expectations are flaky so we shouldn't remove any.
+            Bug(test) test/a.html [ Failure NeedsRebaseline Pass ]
+            Bug(test) test/b.html [ Failure Pass Rebaseline ]
+            Bug(test) test/c.html [ Failure NeedsManualRebaseline Pass ]"""
+
+        self._define_builders({
+            "WebKit Linux": {
+                "port_name": "linux-precise",
+                "specifiers": ['Precise', 'Release']
+            },
+        })
+        self._port._all_build_types = ('release',)
+        self._port._all_systems = (('precise', 'x86_64'),)
+
+        self._parse_expectations(test_expectations_before)
+        self._expectation_factory._all_results_by_builder = {
+            'WebKit Linux': {
+                "test/a.html": ["PASS", "PASS"],
+                "test/b.html": ["PASS", "PASS"],
+                "test/c.html": ["PASS", "PASS"]
+            }
+        }
+        updated_expectations = (
+            self._flake_remover.get_updated_test_expectations())
+        self._assert_expectations_match(
+            updated_expectations, test_expectations_before)
+
+    def test_all_failure_case(self):
+        """Tests that results with all failures are not treated as non-flaky."""
+        test_expectations_before = (
+            """# Keep since it's all failures.
+            Bug(test) test/a.html [ Failure Pass ]""")
+
+        self._define_builders({
+            "WebKit Linux": {
+                "port_name": "linux-precise",
+                "specifiers": ['Precise', 'Release']
+            },
+        })
+        self._port._all_build_types = ('release',)
+        self._port._all_systems = (('precise', 'x86_64'),)
+
+        self._parse_expectations(test_expectations_before)
+        self._expectation_factory._all_results_by_builder = {
+            'WebKit Linux': {
+                "test/a.html": ["IMAGE", "IMAGE", "IMAGE"],
+            }
+        }
+        updated_expectations = (
+            self._flake_remover.get_updated_test_expectations())
+        self._assert_expectations_match(updated_expectations, (
+            """# Keep since it's all failures.
+            Bug(test) test/a.html [ Failure Pass ]"""))
+
+    def test_empty_test_expectations(self):
+        """Running on an empty TestExpectations file outputs an empty file."""
+        test_expectations_before = ""
+
+        self._define_builders({
+            "WebKit Linux": {
+                "port_name": "linux-precise",
+                "specifiers": ['Precise', 'Release']
+            },
+        })
+        self._port._all_build_types = ('release',)
+        self._port._all_systems = (('precise', 'x86_64'),)
+
+        self._parse_expectations(test_expectations_before)
+        self._expectation_factory._all_results_by_builder = {
+            'WebKit Linux': {
+                "test/a.html": ["PASS", "PASS", "PASS"],
+            }
+        }
+        updated_expectations = (
+            self._flake_remover.get_updated_test_expectations())
+        self._assert_expectations_match(updated_expectations, "")
+
+    def test_harness_no_expectations(self):
+        """Tests that a warning is outputted if the TestExpectations file
+        doesn't exist.
+        """
+
+        # Setup the mock host and port.
+        host = MockHost()
+        host.port_factory = FakePortFactory(host)
+
+        # Write the test file but not the TestExpectations file.
+        test_expectation_path = (
+            host.port_factory.get().path_to_generic_test_expectations_file())
+        host.filesystem = MockFileSystem()
+        self._write_tests_into_filesystem(host.filesystem)
+
+        # Write out the fake builder bot results.
+        expectation_factory = FakeBotTestExpectationsFactory()
+        expectation_factory._all_results_by_builder = {}
+
+        self.assertFalse(host.filesystem.isfile(test_expectation_path))
+
+        main(host, expectation_factory, [])
+
+        expected_warning = (
+            "Didn't find generic expectations file at: " +
+            test_expectation_path + "\n")
+        self.assertEqual(self._log_output.getvalue(), expected_warning)
+        self.assertFalse(host.filesystem.isfile(test_expectation_path))