Fetch prefect host and test

tests/test_lolaconfig.py

@@ -91,3 +91,20 @@ def test_lolaconfig_fetches_dw_creds_properly():
     lolaconfig.fetch_dw_credentials(s3_reader=fake_s3_reader)
 
     assert type(lolaconfig.DW_CREDENTIALS) is dict
+
+
+def test_lolaconfig_fetches_prefect_host_properly():
+    lolaconfig = LolaConfig(flow_name="some-flow")
+
+    fake_s3_reader = SimpleNamespace()
+
+    def mock_read_json_from_s3_file(bucket, key):
+        return {
+            "prefect_host": "some_host",
+        }
+
+    fake_s3_reader.read_json_from_s3_file = mock_read_json_from_s3_file
+
+    lolaconfig.fetch_prefect_host(s3_reader=fake_s3_reader)
+
+    assert type(lolaconfig.PREFECT_HOST) is str