From 250b23ccb57538e892fc22218f1dd0c89ad87916 Mon Sep 17 00:00:00 2001
From: Oleksandr Aleksyshyn <97434360+o-aleks@users.noreply.github.com>
Date: Fri, 15 Jul 2022 17:27:05 +0300
Subject: [PATCH 1/2] fix: if JsonObject serialized to None then return
 `null_value` instead of `string_value`

---
 google/cloud/spanner_v1/_helpers.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/google/cloud/spanner_v1/_helpers.py b/google/cloud/spanner_v1/_helpers.py
index 53a73c1a60..b364514d09 100644
--- a/google/cloud/spanner_v1/_helpers.py
+++ b/google/cloud/spanner_v1/_helpers.py
@@ -165,7 +165,11 @@ def _make_value_pb(value):
         _assert_numeric_precision_and_scale(value)
         return Value(string_value=str(value))
     if isinstance(value, JsonObject):
-        return Value(string_value=value.serialize())
+        value = value.serialize()
+        if value is None:
+            return Value(null_value="NULL_VALUE")
+        else:
+            return Value(string_value=value)
 
     raise ValueError("Unknown type: %s" % (value,))
 

From fb7c9170c04c9e9bdf9d6ea1cc758e8abf434e41 Mon Sep 17 00:00:00 2001
From: Oleksandr Aleksyshyn <97434360+o-aleks@users.noreply.github.com>
Date: Wed, 24 Aug 2022 19:30:42 +0300
Subject: [PATCH 2/2] test: covered the case by test

---
 tests/unit/test__helpers.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tests/unit/test__helpers.py b/tests/unit/test__helpers.py
index b18adfa6fe..21434da191 100644
--- a/tests/unit/test__helpers.py
+++ b/tests/unit/test__helpers.py
@@ -306,6 +306,13 @@ def test_w_json(self):
         self.assertIsInstance(value_pb, Value)
         self.assertEqual(value_pb.string_value, value)
 
+    def test_w_json_None(self):
+        from google.cloud.spanner_v1 import JsonObject
+
+        value = JsonObject(None)
+        value_pb = self._callFUT(value)
+        self.assertTrue(value_pb.HasField("null_value"))
+
 
 class Test_make_list_value_pb(unittest.TestCase):
     def _callFUT(self, *args, **kw):