Add unittest for blocking api

Author: kristjanvalur

tests/test_retry.py

@@ -95,6 +95,11 @@ def _do(self):
     def _fail(self, error):
         self.actual_failures += 1
 
+    def _fail_inf(self, error):
+        self.actual_failures += 1
+        if self.actual_failures == 5:
+            raise ConnectionError()
+
     @pytest.mark.parametrize("retries", range(10))
     def test_retry(self, retries):
         backoff = BackoffMock()
@@ -107,6 +112,16 @@ def test_retry(self, retries):
         assert backoff.reset_calls == 1
         assert backoff.calls == retries
 
+    def test_infinite_retry(self):
+        backoff = BackoffMock()
+        # specify infinite retries, but give up after 5
+        retry = Retry(backoff, -1)
+        with pytest.raises(ConnectionError):
+            retry.call_with_retry(self._do, self._fail_inf)
+
+        assert self.actual_attempts == 5
+        assert self.actual_failures == 5
+
 
 @pytest.mark.onlynoncluster
 class TestRedisClientRetry: