Update tests/unit/test_json.py

Co-authored-by: Tim Sweña (Swast) <swast@google.com>

Author: chelsea-lin

tests/unit/test_json.py

@@ -86,7 +86,7 @@ def test_deterministic_json_serialization():
 
 def test_to_numpy():
     data = db_dtypes.JSONArray._from_sequence(JSON_DATA.values())
-    expected = np.asarray(data)
+    expected = np.asarray([json.dumps(value) for value in JSON_DATA.values()])
 
     result = data.to_numpy()
     pd._testing.assert_equal(result, expected)