fix: hash snapshots using correct type for 'update_time' (#467)

Document that 'DocumentSnapshot.create_time' and
'DocumentSnapshot.update_time' are instances of
'proto.datetime_helpers.DatetimeWithNanoseconds'.

Closes #398.
Closes #391.

google/cloud/firestore_v1/base_document.py

@@ -342,11 +342,11 @@ class DocumentSnapshot(object):
         exists (bool):
             Indicates if the document existed at the time the snapshot was
             retrieved.
-        read_time (:class:`google.protobuf.timestamp_pb2.Timestamp`):
+        read_time (:class:`proto.datetime_helpers.DatetimeWithNanoseconds`):
             The time that this snapshot was read from the server.
-        create_time (:class:`google.protobuf.timestamp_pb2.Timestamp`):
+        create_time (:class:`proto.datetime_helpers.DatetimeWithNanoseconds`):
             The time that this document was created.
-        update_time (:class:`google.protobuf.timestamp_pb2.Timestamp`):
+        update_time (:class:`proto.datetime_helpers.DatetimeWithNanoseconds`):
             The time that this document was last updated.
     """
 
@@ -368,9 +368,7 @@ def __eq__(self, other):
         return self._reference == other._reference and self._data == other._data
 
     def __hash__(self):
-        seconds = int(self.update_time.timestamp())
-        nanos = self.update_time.nanosecond
-        return hash(self._reference) + hash(seconds) + hash(nanos)
+        return hash(self._reference) + hash(self.update_time)
 
     @property
     def _client(self):

tests/system/test_system.py

@@ -1584,8 +1584,7 @@ def test_repro_429(client, cleanup):
     now = datetime.datetime.utcnow().replace(tzinfo=UTC)
     collection = client.collection("repro-429" + UNIQUE_RESOURCE_ID)
 
-    document_ids = [f"doc-{doc_id:02d}" for doc_id in range(30)]
-    for document_id in document_ids:
+    for document_id in [f"doc-{doc_id:02d}" for doc_id in range(30)]:
         data = {"now": now, "paymentId": None}
         _, document = collection.add(data, document_id)
         cleanup(document.delete)
@@ -1601,3 +1600,17 @@ def test_repro_429(client, cleanup):
 
     for snapshot in query2.stream():
         print(f"id: {snapshot.id}")
+
+
+def test_repro_391(client, cleanup):
+    # See: https://github.com/googleapis/python-firestore/issues/391
+    now = datetime.datetime.utcnow().replace(tzinfo=UTC)
+    collection = client.collection("repro-391" + UNIQUE_RESOURCE_ID)
+
+    document_ids = [f"doc-{doc_id:02d}" for doc_id in range(30)]
+
+    for document_id in [f"doc-{doc_id:02d}" for doc_id in range(30)]:
+        data = {"now": now}
+        _, document = collection.add(data, document_id)
+
+    assert len(set(collection.stream())) == len(document_ids)

tests/unit/v1/test_base_document.py

@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
 import unittest
 
 import mock
 from proto.datetime_helpers import DatetimeWithNanoseconds
-from google.protobuf import timestamp_pb2
 
 
 class TestBaseDocumentReference(unittest.TestCase):
@@ -274,15 +274,13 @@ def test___hash__(self):
         client.__hash__.return_value = 234566789
         reference = self._make_reference("hi", "bye", client=client)
         data = {"zoop": 83}
-        update_time = DatetimeWithNanoseconds.from_timestamp_pb(
-            timestamp_pb2.Timestamp(seconds=123456, nanos=123456789)
+        update_time = DatetimeWithNanoseconds(
+            2021, 10, 4, 17, 43, 27, nanosecond=123456789, tzinfo=datetime.timezone.utc
         )
         snapshot = self._make_one(
             reference, data, True, None, mock.sentinel.create_time, update_time
         )
-        self.assertEqual(
-            hash(snapshot), hash(reference) + hash(123456) + hash(123456789)
-        )
+        self.assertEqual(hash(snapshot), hash(reference) + hash(update_time))
 
     def test__client_property(self):
         reference = self._make_reference(