Add support for 'None' on response data

tests/unit/conftest.py

@@ -185,6 +185,29 @@ def sample_get_response_data():
     }
 
 
+@pytest.fixture(scope="session")
+def sample_get_response_data_none():
+    """
+    This is the response to the second HTTP request (a GET) from an actual
+    Trino session. It is deliberately not truncated to document such response
+    and allow to use it for other tests. After doing the steps above, do:
+
+    ::
+        >>> cur.fetchall()
+
+    """
+    yield {
+        "id": "20210817_140827_00000_arvdv",
+        "nextUri": "coordinator:8080/v1/statement/20210817_140827_00000_arvdv/2",
+        "data": None,
+        "columns": [],
+        "taskDownloadUris": [],
+        "partialCancelUri": "http://localhost:8080/v1/stage/20210817_140827_00000_arvdv.0",  # NOQA: E501
+        "stats": {},
+        "infoUri": "http://coordinator:8080/query.html?20210817_140827_00000_arvdv",  # NOQA: E501
+    }
+
+
 @pytest.fixture(scope="session")
 def sample_get_error_response_data():
     yield {

tests/unit/test_client.py

@@ -704,6 +704,32 @@ def test_trino_fetch_request(mock_requests, sample_get_response_data):
     assert status.rows == sample_get_response_data["data"]
 
 
+@mock.patch("trino.client.TrinoRequest.http")
+def test_trino_fetch_request_data_none(mock_requests, sample_get_response_data_none):
+    mock_requests.Response.return_value.json.return_value = sample_get_response_data_none
+
+    req = TrinoRequest(
+        host="coordinator",
+        port=8080,
+        client_session=ClientSession(
+            user="test",
+            source="test",
+            catalog="test",
+            schema="test",
+            properties={},
+        ),
+        http_scheme="http",
+    )
+
+    http_resp = TrinoRequest.http.Response()
+    http_resp.status_code = 200
+    status = req.process(http_resp)
+
+    assert status.next_uri == sample_get_response_data_none["nextUri"]
+    assert status.id == sample_get_response_data_none["id"]
+    assert status.rows == []
+
+
 @mock.patch("trino.client.TrinoRequest.http")
 def test_trino_fetch_error(mock_requests, sample_get_error_response_data):
     mock_requests.Response.return_value.json.return_value = sample_get_error_response_data

trino/client.py

@@ -633,6 +633,8 @@ def process(self, http_response) -> TrinoStatus:
 
         self._next_uri = response.get("nextUri")
 
+        data = response.get("data") if response.get("data") else []
+
         return TrinoStatus(
             id=response["id"],
             stats=response["stats"],
@@ -641,7 +643,7 @@ def process(self, http_response) -> TrinoStatus:
             next_uri=self._next_uri,
             update_type=response.get("updateType"),
             update_count=response.get("updateCount"),
-            rows=response.get("data", []),
+            rows=data,
             columns=response.get("columns"),
         )