def testMixins(self):
    self.VerifyContentsProducesOutput('\n.mixed-in {\n  --css-mixin: {\n    color: red;\n  }\n}', '\n- Avoid using CSS mixins. Use CSS shadow parts, CSS variables, or common CSS classes instead.\n    --css-mixin: {')
def testMixins(self):
    self.VerifyContentsProducesOutput('\n.mixed-in {\n  --css-mixin: {\n    color: red;\n  }\n}', '\n- Avoid using CSS mixins. Use CSS shadow parts, CSS variables, or common CSS classes instead.\n    --css-mixin: {')