Add a bunch more legacy API tests

src/flake8/api/legacy.py

@@ -115,8 +115,9 @@ class StyleGuide(object):
 
     def init_report(self, reporter=None):
         """Set up a formatter for this run of Flake8."""
-        if (reporter is not None and
-                not issubclass(reporter, formatter.BaseFormatter)):
+        if reporter is None:
+            return
+        if not issubclass(reporter, formatter.BaseFormatter):
             raise ValueError("Report should be subclass of "
                              "flake8.formatter.BaseFormatter.")
         self._application.make_formatter(reporter)

tests/unit/test_legacy_api.py

@@ -1,7 +1,9 @@
 """Tests for Flake8's legacy API."""
 import mock
+import pytest
 
 from flake8.api import legacy as api
+from flake8.formatting import base as formatter
 
 
 def test_get_style_guide():
@@ -48,3 +50,96 @@ def test_styleguide_check_files():
     app.run_checks.assert_called_once_with(paths)
     app.report_errors.assert_called_once_with()
     assert isinstance(report, api.Report)
+
+
+def test_styleguide_excluded():
+    """Verify we delegate to our file checker manager.
+
+    We also want to ensure that if we don't specify a parent, is_path_excluded
+    is called exactly once.
+    """
+    app = mock.Mock()
+    file_checker_manager = app.file_checker_manager = mock.Mock()
+    style_guide = api.StyleGuide(app)
+
+    style_guide.excluded('file.py')
+    file_checker_manager.is_path_excluded.assert_called_once_with('file.py')
+
+
+def test_styleguide_excluded_with_parent():
+    """Verify we delegate to our file checker manager.
+
+    When we add the parent argument, we don't check that is_path_excluded was
+    called only once.
+    """
+    app = mock.Mock()
+    file_checker_manager = app.file_checker_manager = mock.Mock()
+    style_guide = api.StyleGuide(app)
+
+    style_guide.excluded('file.py', 'parent')
+    file_checker_manager.is_path_excluded.call_args == [
+        ('file.py',),
+        ('parent/file.py',),
+    ]
+
+
+def test_styleguide_init_report_does_nothing():
+    """Verify if we use None that we don't call anything."""
+    app = mock.Mock()
+    style_guide = api.StyleGuide(app)
+    style_guide.init_report()
+    assert app.make_formatter.called is False
+    assert app.make_guide.called is False
+
+
+def test_styleguide_init_report_with_non_subclass():
+    """Verify we raise a ValueError with non BaseFormatter subclasses."""
+    app = mock.Mock()
+    style_guide = api.StyleGuide(app)
+    with pytest.raises(ValueError):
+        style_guide.init_report(object)
+    assert app.make_formatter.called is False
+    assert app.make_guide.called is False
+
+
+def test_styleguide_init_report():
+    """Verify we do the right incantation for the Application."""
+    app = mock.Mock(guide='fake')
+    style_guide = api.StyleGuide(app)
+
+    class FakeFormatter(formatter.BaseFormatter):
+        def format(self, *args):
+            pass
+
+    style_guide.init_report(FakeFormatter)
+    app.make_formatter.assert_called_once_with(FakeFormatter)
+    assert app.guide is None
+    app.make_guide.assert_called_once_with()
+
+
+def test_styleguide_input_file():
+    """Verify we call StyleGuide.check_files with the filename."""
+    app = mock.Mock()
+    style_guide = api.StyleGuide(app)
+    with mock.patch.object(style_guide, 'check_files') as check_files:
+        style_guide.input_file('file.py')
+    check_files.assert_called_once_with(['file.py'])
+
+
+def test_report_total_errors():
+    """Verify total errors is just a proxy attribute."""
+    app = mock.Mock(result_count='Fake count')
+    report = api.Report(app)
+    assert report.total_errors == 'Fake count'
+
+
+def test_report_get_statistics():
+    """Verify that we use the statistics object."""
+    stats = mock.Mock()
+    stats.statistics_for.return_value = []
+    style_guide = mock.Mock(stats=stats)
+    app = mock.Mock(guide=style_guide)
+
+    report = api.Report(app)
+    assert report.get_statistics('E') == []
+    stats.statistics_for.assert_called_once_with('E')