docstring and tests

Author: Linchin

google/cloud/bigquery/schema.py

@@ -197,7 +197,7 @@ class SchemaField(object):
             Only valid for top-level schema fields (not nested fields).
             If the type is FOREIGN, this field is required.
 
-        timestamp_precision: Union[enums.TimestampPrecision, int, None]
+        timestamp_precision: Optional[enums.TimestampPrecision]
             Precision (maximum number of total digits in base 10) for seconds
             of TIMESTAMP type.
 
@@ -391,9 +391,12 @@ def policy_tags(self):
         return PolicyTagList.from_api_repr(resource) if resource is not None else None
 
     @property
-    def timestamp_precision(self):
-        """Union[enums.TimestampPrecision, int, None]: Precision (maximum number
-        of total digits in base 10) for seconds of TIMESTAMP type.
+    def timestamp_precision(self) -> enums.TimestampPrecision:
+        """Precision (maximum number of total digits in base 10) for seconds of
+        TIMESTAMP type.
+
+        Returns:
+            enums.TimestampPrecision: value of TimestampPrecision.
         """
         return enums.TimestampPrecision(self._properties.get("timestampPrecision"))
 

tests/unit/test_schema.py

@@ -223,7 +223,7 @@ def test_from_api_repr(self):
                 "name": "foo",
                 "type": "record",
                 "roundingMode": "ROUNDING_MODE_UNSPECIFIED",
-                "timestampPrecision": enums.TimestampPrecision.PICOSECOND,
+                "timestampPrecision": 12,
             }
         )
         self.assertEqual(field.name, "foo")
@@ -237,7 +237,7 @@ def test_from_api_repr(self):
         self.assertEqual(field.range_element_type, None)
         self.assertEqual(field.rounding_mode, "ROUNDING_MODE_UNSPECIFIED")
         self.assertEqual(
-            field._properties["timestampPrecision"],
+            field.timestamp_precision,
             enums.TimestampPrecision.PICOSECOND,
         )
 
@@ -356,7 +356,9 @@ def test_foreign_type_definition_property_str(self):
     def test_timestamp_precision_property(self):
         TIMESTAMP_PRECISION = enums.TimestampPrecision.PICOSECOND
         schema_field = self._make_one("test", "TIMESTAMP")
-        schema_field._properties["timestampPrecision"] = TIMESTAMP_PRECISION
+        schema_field._properties[
+            "timestampPrecision"
+        ] = enums.TimestampPrecision.PICOSECOND.value
         self.assertEqual(schema_field.timestamp_precision, TIMESTAMP_PRECISION)
 
     def test_to_standard_sql_simple_type(self):