adjust old test for orjson datetime64 fixed precision

Author: alexcjohnson

Diff for: packages/python/plotly/plotly/tests/test_io/test_to_from_plotly_json.py

@@ -6,6 +6,7 @@
 import pandas as pd
 import json
 import datetime
+import re
 import sys
 from pytz import timezone
 from _plotly_utils.optional_imports import get_module
@@ -201,6 +202,14 @@ def to_str(v):
 
     array_str = to_json_test(dt_values)
     expected = build_test_dict_string(array_str)
+    if orjson:
+        # orjson always serializes datetime64 to ns, but json will return either
+        # full seconds or microseconds, if the rest is zeros.
+        # we don't care about any trailing zeros
+        trailing_zeros = re.compile(r'[.]?0+"')
+        result = trailing_zeros.sub('"', result)
+        expected = trailing_zeros.sub('"', expected)
+
     assert result == expected
     check_roundtrip(result, engine=engine, pretty=pretty)