updates logic and tests related to _isinstance_or_raise'

Author: chalmerlowe

google/cloud/bigquery/_helpers.py

@@ -23,7 +23,7 @@
 import re
 import os
 import warnings
-from typing import Optional, Union, Any, Tuple
+from typing import Optional, Union, Any, Tuple, Type
 
 from dateutil import relativedelta
 from google.cloud._helpers import UTC  # type: ignore
@@ -1031,13 +1031,18 @@ def from_api_repr(cls, resource: dict):
         return config
 
 
-def _isinstance_or_raise(value: Any, dtype: type, none_allowed: Optional[bool]):
+def _isinstance_or_raise(
+        value: Any,
+        dtype: Union[Type, Tuple[Type, ...]],
+        none_allowed: Optional[bool]=False,
+    ) -> Any:
     """Determine whether a value type matches a given datatype or None.
 
     Args:
         value (Any): Value to be checked.
-        dtype (type): Expected data type(s).
-        none_allowed Optional(bool): whether value is allowed to be None.
+        dtype (type): Expected data type or tuple of data types.
+        none_allowed Optional(bool): whether value is allowed to be None. Default
+           is False.
 
     Returns:
         Any: Returns the input value if the type check is successful.
@@ -1051,5 +1056,9 @@ def _isinstance_or_raise(value: Any, dtype: type, none_allowed: Optional[bool]):
     if isinstance(value, dtype):
         return value
 
-    msg = f"Pass {value} as a '{dtype}' (or None). Got {type(value)}." # Add the 'or None' conditionally
+    or_none = ''
+    if none_allowed:
+        or_none = ' (or None)'
+
+    msg = f"Pass {value} as a '{dtype}'{or_none}. Got {type(value)}."
     raise TypeError(msg)

tests/unit/test__helpers.py

@@ -1666,35 +1666,34 @@ def test_w_env_var(self):
 
 class Test__isinstance_or_raise:
     @pytest.mark.parametrize(
-        "value,dtype,expected",
+        "value,dtype,none_allowed,expected",
         [
-            (None, None, None),
-            ('hello world.uri', str, 'hello world.uri'),
-            (None, (str, None), None),
-            (None, (None, str), None),
-            (None, (str, None), None),
-            ('hello world.uri', (None, str), 'hello world.uri'),
-            ('hello world.uri', (str, None), 'hello world.uri'),
+            (None, str, True, None),
+            ('hello world.uri', str, True, 'hello world.uri'),
+            ('hello world.uri', str, False, 'hello world.uri'),
+            (None, (str, float), True, None),
+            ('hello world.uri', (str, float), True, 'hello world.uri'),
+            ('hello world.uri', (str, float), False, 'hello world.uri'),
         ],
     )
-    def test__valid_isinstance_or_raise(self, value, dtype, expected):
-        result = _isinstance_or_raise(value, dtype)
+    def test__valid_isinstance_or_raise(self, value, dtype, none_allowed, expected):
+        result = _isinstance_or_raise(value, dtype, none_allowed=none_allowed)
 
         assert result == expected
 
     @pytest.mark.parametrize(
-        "value,dtype,expected",
+        "value,dtype,none_allowed,expected",
         [
-            (None, str, pytest.raises(TypeError)),
-            ({"key": "value"}, str, pytest.raises(TypeError)),
-            ({"key": "value"}, None, pytest.raises(TypeError)),
-            ({"key": "value"}, (str, None), pytest.raises(TypeError)),
-            ({"key": "value"}, (None, str), pytest.raises(TypeError)),
+            (None, str, False, pytest.raises(TypeError)),
+            ({"key": "value"}, str, True, pytest.raises(TypeError)),
+            ({"key": "value"}, str, False, pytest.raises(TypeError)),
+            ({"key": "value"}, (str, float), True, pytest.raises(TypeError)),
+            ({"key": "value"}, (str, float), False, pytest.raises(TypeError)),
         ],
     )
-    def test__invalid_isinstance_or_raise(self, value, dtype, expected):
+    def test__invalid_isinstance_or_raise(self, value, dtype, none_allowed, expected):
         with expected as e:
-            result = _isinstance_or_raise(value, dtype)
+            result = _isinstance_or_raise(value, dtype, none_allowed=none_allowed)
 
             assert result == e