# Type of request: This is a ...
[ ] bug report
[x] feature request

# Detailed description
As a Developer,
I want to be able to simulate BadDigest and InvalidDigest errors,
So that I can test the error handling logic

## Expected behavior
https://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
BadDigest: The Content-MD5 you specified did not match what we received.
InvalidDigest: The Content-MD5 you specified is not valid.

## Actual behavior
localstack returns InvalidDigest when MD5 does not match payload.


arn = lambda_api.func_arn(self.FUNCTION_NAME)
            response = self.client.get('{0}/tags/{1}'.format(lambda_api.PATH_ROOT, arn))
            result = json.loads(response.get_data())
            self.assertTrue('Tags' in result)
            self.assertDictEqual(self.TAGS, result['Tags'])
    def test_tag_resource(self):
        with self.app.test_request_context():
            self._create_function(self.FUNCTION_NAME)
            arn = lambda_api.func_arn(self.FUNCTION_NAME)
            response = self.client.get('{0}/tags/{1}'.format(lambda_api.PATH_ROOT, arn))
            result = json.loads(response.get_data())
            self.assertTrue('Tags' in result)
            self.assertDictEqual({}, result['Tags'])
            self.client.post('{0}/tags/{1}'.format(lambda_api.PATH_ROOT, arn), data=json.dumps({'Tags': self.TAGS}))
            response = self.client.get('{0}/tags/{1}'.format(lambda_api.PATH_ROOT, arn))
            result = json.loads(response.get_data())
            self.assertTrue('Tags' in result)
            self.assertDictEqual(self.TAGS, result['Tags'])
    def test_tag_non_existent_function_returns_error(self):
        with self.app.test_request_context():
            arn = lambda_api.func_arn('non-existent-function')
            response = self.client.post(
                '{0}/tags/{1}'.format(lambda_api.PATH_ROOT, arn),
                data=json.dumps({'Tags': self.TAGS}))
            result = json.loads(response.get_data())
            self.assertEqual(self.RESOURCENOTFOUND_EXCEPTION, result['__type'])
            self.assertEqual(
                self.RESOURCENOTFOUND_MESSAGE % arn,
                result['message'])
    def test_untag_resource(self):