added unit test to protect fix

Author: sciros

tests/unit/aws_lambda_mpic/test_dcv_checker_lambda.py

@@ -1,5 +1,12 @@
+import asyncio
 import time
+from asyncio import StreamReader
+from unittest.mock import MagicMock, AsyncMock
+
 import pytest
+from aiohttp import ClientResponse
+from multidict import CIMultiDictProxy, CIMultiDict
+from yarl import URL
 
 import aws_lambda_mpic.mpic_dcv_checker_lambda.mpic_dcv_checker_lambda_function as mpic_dcv_checker_lambda_function
 from open_mpic_core.common_domain.validation_error import MpicValidationError
@@ -9,6 +16,7 @@
 from open_mpic_core_test.test_util.valid_check_creator import ValidCheckCreator
 
 
+# noinspection PyMethodMayBeStatic
 class TestDcvCheckerLambda:
     @staticmethod
     @pytest.fixture(scope='class')
@@ -53,6 +61,31 @@ def lambda_handler__should_return_appropriate_status_code_given_errors_in_respon
         result = mpic_dcv_checker_lambda_function.lambda_handler(dcv_check_request, None)
         assert result == mock_return_value
 
+    def lambda_handler__should_ensure_dcv_checker_is_fully_initialized_to_perform_http_based_checks(self, set_env_variables, mocker):
+        dcv_check_request = ValidCheckCreator.create_valid_http_check_request()
+        expected_challenge_value = dcv_check_request.dcv_check_parameters.validation_details.challenge_value
+
+        # this test requires getting pretty far into the Dcv Checker execution; need to mock an aiohttp.ClientResponse
+        event_loop = asyncio.get_event_loop()
+        response = ClientResponse(
+            method='GET', url=URL('http://example.com'), writer=MagicMock(), continue100=None,
+            timer=AsyncMock(), request_info=AsyncMock(), traces=[], loop=event_loop, session=AsyncMock()
+        )
+        response.status = 200
+        response.content = StreamReader(loop=event_loop)
+        response.content.feed_data(bytes(expected_challenge_value.encode('utf-8')))
+        response.content.feed_eof()
+        response._headers = CIMultiDictProxy(CIMultiDict({
+            'Content-Type': 'text/plain; charset=utf-8', 'Content-Length': str(len(expected_challenge_value))
+        }))
+
+        mocker.patch(
+            'aiohttp.ClientSession.get',
+            side_effect=lambda *args, **kwargs: AsyncMock(__aenter__=AsyncMock(return_value=response))
+        )
+        result = mpic_dcv_checker_lambda_function.lambda_handler(dcv_check_request, None)
+        assert result['statusCode'] == 200
+
     @staticmethod
     def create_dcv_check_response():
         return DcvCheckResponse(perspective_code='us-east-1', check_passed=True,