    def test_it_validates_using_draft7_when_specified(self):
        """
        Specifically, `const` validation applies for Draft 7.
        """
        schema = """
            {
                "$schema": "http://json-schema.org/draft-07/schema#",
                "const": "check"
            }
        """
        instance = '"foo"'
        self.assertOutputs(
            files=dict(some_schema=schema, some_instance=instance),
            argv=["-i", "some_instance", "some_schema"],
            exit_code=1,
            stdout="",
            stderr="foo: 'check' was expected\n",
        )
Specifically, `const` validation applies for Draft 7.
jsonschema/tests/test_cli.py