Fix explicit schema resolution

Author: Abacn

sdks/python/apache_beam/io/external/xlang_jdbcio_it_test.py

@@ -30,6 +30,7 @@
 
 import apache_beam as beam
 from apache_beam import coders
+from apache_beam.io import jdbc
 from apache_beam.io.jdbc import ReadFromJdbc
 from apache_beam.io.jdbc import WriteToJdbc
 from apache_beam.options.pipeline_options import StandardOptions
@@ -82,7 +83,13 @@
         ("renamed_time", datetime.time),
     ],
 )
-coders.registry.register_row(CustomSchemaRow)
+
+# Need to put inside enforce_millis_instant_for_timestamp context to align
+# with the same setup in ReadFromJdbc.__init__. Remove once Beam moved to
+# micros instant for timestamp
+# Alternatively, use coders.registry.register_coder(CustomSchemaRow, RowCoder)
+with jdbc.enforce_millis_instant_for_timestamp():
+  coders.registry.register_row(CustomSchemaRow)
 
 SimpleRow = typing.NamedTuple(
     "SimpleRow", [("id", int), ("name", str), ("value", float)])