Add tests for the expected behaviour of per-file-ignores

These show that there were some subtle bugs in how we were matching
things and that there are bugs that need to be fixed.

tests/unit/test_style_guide.py

@@ -5,6 +5,7 @@ import mock
 import pytest
 
 from flake8 import style_guide
+from flake8 import utils
 from flake8.formatting import base
 from flake8.plugins import notifier
 
@@ -17,6 +18,7 @@ def create_options(**kwargs):
     kwargs.setdefault('extend_ignore', [])
     kwargs.setdefault('disable_noqa', False)
     kwargs.setdefault('enable_extensions', [])
+    kwargs.setdefault('per_file_ignores', [])
     return optparse.Values(kwargs)
 
 
@@ -81,3 +83,101 @@ def test_handle_error_does_not_notify_listeners(select_list, ignore_list,
         guide.handle_error(error_code, 'stdin', 1, 1, 'error found')
     assert listener_trie.notify.called is False
     assert formatter.handle.called is False
+
+
+def test_style_guide_manager():
+    """Verify how the StyleGuideManager creates a default style guide."""
+    listener_trie = mock.create_autospec(notifier.Notifier, instance=True)
+    formatter = mock.create_autospec(base.BaseFormatter, instance=True)
+    options = create_options()
+    guide = style_guide.StyleGuideManager(options,
+                                          listener_trie=listener_trie,
+                                          formatter=formatter)
+    assert guide.default_style_guide.options is options
+    assert len(guide.style_guides) == 1
+
+
+PER_FILE_IGNORES_UNPARSED = [
+    "first_file.py:W9",
+    "second_file.py:F4,F9",
+    "third_file.py:E3",
+    "sub_dir/*:F4",
+]
+
+
+@pytest.mark.parametrize('style_guide_file,filename,expected', [
+    ("first_file.py", "first_file.py", True),
+    ("first_file.py", "second_file.py", False),
+    ("sub_dir/*.py", "first_file.py", False),
+    ("sub_dir/*.py", "sub_dir/file.py", True),
+    ("sub_dir/*.py", "other_dir/file.py", False),
+])
+def test_style_guide_applies_to(style_guide_file, filename, expected):
+    """Verify that we match a file to its style guide."""
+    listener_trie = mock.create_autospec(notifier.Notifier, instance=True)
+    formatter = mock.create_autospec(base.BaseFormatter, instance=True)
+    options = create_options()
+    guide = style_guide.StyleGuide(options,
+                                   listener_trie=listener_trie,
+                                   formatter=formatter,
+                                   filename=style_guide_file)
+    assert guide.applies_to(filename) is expected
+
+
+def test_style_guide_manager_pre_file_ignores_parsing():
+    """Verify how the StyleGuideManager creates a default style guide."""
+    listener_trie = mock.create_autospec(notifier.Notifier, instance=True)
+    formatter = mock.create_autospec(base.BaseFormatter, instance=True)
+    options = create_options(per_file_ignores=PER_FILE_IGNORES_UNPARSED)
+    guide = style_guide.StyleGuideManager(options,
+                                          listener_trie=listener_trie,
+                                          formatter=formatter)
+    assert len(guide.style_guides) == 5
+    assert list(map(utils.normalize_path,
+                    ["first_file.py", "second_file.py", "third_file.py",
+                        "sub_dir/*"])
+                ) == [g.filename for g in guide.style_guides[1:]]
+
+
+@pytest.mark.parametrize('ignores,violation,filename,handle_error_return', [
+    (['E1', 'E2'], 'F401', 'first_file.py', 1),
+    (['E1', 'E2'], 'E121', 'first_file.py', 0),
+    (['E1', 'E2'], 'F401', 'second_file.py', 0),
+    (['E1', 'E2'], 'F401', 'third_file.py', 1),
+    (['E1', 'E2'], 'E311', 'third_file.py', 0),
+    (['E1', 'E2'], 'F401', 'sub_dir/file.py', 0),
+])
+def test_style_guide_manager_pre_file_ignores(ignores, violation, filename,
+                                              handle_error_return):
+    """Verify how the StyleGuideManager creates a default style guide."""
+    listener_trie = mock.create_autospec(notifier.Notifier, instance=True)
+    formatter = mock.create_autospec(base.BaseFormatter, instance=True)
+    options = create_options(ignore=ignores,
+                             select=['E', 'F', 'W'],
+                             per_file_ignores=PER_FILE_IGNORES_UNPARSED)
+    guide = style_guide.StyleGuideManager(options,
+                                          listener_trie=listener_trie,
+                                          formatter=formatter)
+    assert (guide.handle_error(violation, filename, 1, 1, "Fake text")
+            == handle_error_return)
+
+
+@pytest.mark.parametrize('filename,expected', [
+    ('first_file.py', utils.normalize_path('first_file.py')),
+    ('second_file.py', utils.normalize_path('second_file.py')),
+    ('third_file.py', utils.normalize_path('third_file.py')),
+    ('fourth_file.py', None),
+    ('sub_dir/__init__.py', utils.normalize_path('sub_dir/*')),
+    ('other_dir/__init__.py', None),
+])
+def test_style_guide_manager_style_guide_for(filename, expected):
+    """Verify the style guide selection function."""
+    listener_trie = mock.create_autospec(notifier.Notifier, instance=True)
+    formatter = mock.create_autospec(base.BaseFormatter, instance=True)
+    options = create_options(per_file_ignores=PER_FILE_IGNORES_UNPARSED)
+    guide = style_guide.StyleGuideManager(options,
+                                          listener_trie=listener_trie,
+                                          formatter=formatter)
+
+    file_guide = guide.style_guide_for(filename)
+    assert file_guide.filename == expected