ViewsPluginStyleMappingTest::mappedOutputHelper in core/modules/views/tests/styles/views_plugin_style_mapping.test

Tests the mapping of fields.

ViewsPluginStyleTestCase::testCustomRowClasses in core/modules/views/tests/styles/views_plugin_style.test

Tests custom css classes.

ViewsPluginStyleUnformattedTestCase::testDefaultRowClasses in core/modules/views/tests/styles/views_plugin_style_unformatted.test

Take sure that the default css classes works as expected.