Add tests for the Plugin class

tests/unit/test_plugin.py

@@ -0,0 +1,144 @@
+"""Tests for flake8.plugins.manager.Plugin."""
+import mock
+
+from flake8.plugins import manager
+
+
+def test_load_plugin_fallsback_on_old_setuptools():
+    """Verify we fallback gracefully to on old versions of setuptools."""
+    entry_point = mock.Mock(spec=['load'])
+    plugin = manager.Plugin('T000', entry_point)
+
+    plugin.load_plugin()
+    entry_point.load.assert_called_once_with(require=False)
+
+
+def test_load_plugin_avoids_deprecated_entry_point_methods():
+    """Verify we use the preferred methods on new versions of setuptools."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin = manager.Plugin('T000', entry_point)
+
+    plugin.load_plugin(verify_requirements=True)
+    assert entry_point.load.called is False
+    entry_point.require.assert_called_once_with()
+    entry_point.resolve.assert_called_once_with()
+
+
+def test_load_plugin_is_idempotent():
+    """Verify we use the preferred methods on new versions of setuptools."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin = manager.Plugin('T000', entry_point)
+
+    plugin.load_plugin(verify_requirements=True)
+    plugin.load_plugin(verify_requirements=True)
+    plugin.load_plugin()
+    assert entry_point.load.called is False
+    entry_point.require.assert_called_once_with()
+    entry_point.resolve.assert_called_once_with()
+
+
+def test_load_plugin_only_calls_require_when_verifying_requirements():
+    """Verify we do not call require when verify_requirements is False."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin = manager.Plugin('T000', entry_point)
+
+    plugin.load_plugin()
+    assert entry_point.load.called is False
+    assert entry_point.require.called is False
+    entry_point.resolve.assert_called_once_with()
+
+
+def test_plugin_property_loads_plugin_on_first_use():
+    """Verify that we load our plugin when we first try to use it."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin = manager.Plugin('T000', entry_point)
+
+    assert plugin.plugin is not None
+    entry_point.resolve.assert_called_once_with()
+
+
+def test_execute_calls_plugin_with_passed_arguments():
+    """Verify that we pass arguments directly to the plugin."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin_obj = mock.Mock()
+    plugin = manager.Plugin('T000', entry_point)
+    plugin._plugin = plugin_obj
+
+    plugin.execute('arg1', 'arg2', kwarg1='value1', kwarg2='value2')
+    plugin_obj.assert_called_once_with(
+        'arg1', 'arg2', kwarg1='value1', kwarg2='value2'
+    )
+
+    # Extra assertions
+    assert entry_point.load.called is False
+    assert entry_point.require.called is False
+    assert entry_point.resolve.called is False
+
+
+def test_version_proxies_to_the_plugin():
+    """Verify that we pass arguments directly to the plugin."""
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin_obj = mock.Mock(spec_set=['version'])
+    plugin_obj.version = 'a.b.c'
+    plugin = manager.Plugin('T000', entry_point)
+    plugin._plugin = plugin_obj
+
+    assert plugin.version == 'a.b.c'
+
+
+def test_register_options():
+    """Verify we call add_options on the plugin only if it exists."""
+    # Set up our mocks and Plugin object
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin_obj = mock.Mock(spec_set=['name', 'version', 'add_options',
+                                     'parse_options'])
+    option_manager = mock.Mock(spec=['register_plugin'])
+    plugin = manager.Plugin('T000', entry_point)
+    plugin._plugin = plugin_obj
+
+    # Call the method we're testing.
+    plugin.register_options(option_manager)
+
+    # Assert that we call add_options
+    plugin_obj.add_options.assert_called_once_with(option_manager)
+    # Assert that we register the plugin
+    option_manager.register_plugin.assert_called_once_with(
+        entry_point_name='T000',
+        version=plugin_obj.version,
+        name=plugin_obj.name,
+    )
+
+
+def test_register_options_checks_plugin_for_method():
+    """Verify we call add_options on the plugin only if it exists."""
+    # Set up our mocks and Plugin object
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin_obj = mock.Mock(spec_set=['name', 'version', 'parse_options'])
+    option_manager = mock.Mock(spec=['register_plugin'])
+    plugin = manager.Plugin('T000', entry_point)
+    plugin._plugin = plugin_obj
+
+    # Call the method we're testing.
+    plugin.register_options(option_manager)
+
+    # Assert that we register the plugin
+    assert option_manager.register_plugin.called is False
+
+
+def test_provide_options():
+    """Verify we call add_options on the plugin only if it exists."""
+    # Set up our mocks and Plugin object
+    entry_point = mock.Mock(spec=['require', 'resolve', 'load'])
+    plugin_obj = mock.Mock(spec_set=['name', 'version', 'add_options',
+                                     'parse_options'])
+    option_manager = mock.Mock()
+    plugin = manager.Plugin('T000', entry_point)
+    plugin._plugin = plugin_obj
+
+    # Call the method we're testing.
+    plugin.provide_options(option_manager, 'options', None)
+
+    # Assert that we call add_options
+    plugin_obj.parse_options.assert_called_once_with(
+        option_manager, 'options', None
+    )