fix(warnings): remove faulty MissingSpecAttributeWarning (#263)

Closes #257

Author: mcous

decoy/spy_core.py

@@ -16,7 +16,7 @@
 )
 
 from .spy_events import SpyInfo
-from .warnings import IncorrectCallWarning, MissingSpecAttributeWarning
+from .warnings import IncorrectCallWarning
 
 
 class _FROM_SOURCE:
@@ -123,15 +123,12 @@ def create_child_core(self, name: str, is_async: bool) -> "SpyCore":
         source = self._source
         child_name = f"{self._name}.{name}"
         child_source = None
-        child_found = False
 
         if inspect.isclass(source):
             # use type hints to get child spec for class attributes
             child_hint = _get_type_hints(source).get(name)
             # use inspect to get child spec for methods and properties
             child_source = inspect.getattr_static(source, name, child_hint)
-            # record whether a child was found before we make modifications
-            child_found = child_source is not None
 
             if isinstance(child_source, property):
                 child_source = _get_type_hints(child_source.fget).get("return")
@@ -152,13 +149,6 @@ def create_child_core(self, name: str, is_async: bool) -> "SpyCore":
 
         child_source = _unwrap_optional(child_source)
 
-        if source is not None and child_found is False:
-            # stacklevel: 4 ensures warning is linked to call location
-            warnings.warn(
-                MissingSpecAttributeWarning(f"{self._name} has no attribute '{name}'"),
-                stacklevel=4,
-            )
-
         return SpyCore(
             source=child_source,
             name=child_name,

decoy/warnings.py

@@ -96,13 +96,3 @@ class IncorrectCallWarning(DecoyWarning):
 
     [IncorrectCallWarning guide]: usage/errors-and-warnings.md#incorrectcallwarning
     """
-
-
-class MissingSpecAttributeWarning(DecoyWarning):
-    """A warning raised if a Decoy mock with a spec is used with a missing attribute.
-
-    This will become an error in the next major version of Decoy.
-    See the [MissingSpecAttributeWarning guide][] for more details.
-
-    [MissingSpecAttributeWarning guide]: usage/errors-and-warnings.md#missingspecattributewarning
-    """

docs/usage/errors-and-warnings.md

@@ -80,8 +80,8 @@ pytestmark = pytest.mark.filterwarnings("ignore::decoy.warnings.DecoyWarning")
 
 A [decoy.warnings.MiscalledStubWarning][] is a warning provided mostly for productivity convenience. If you configure a stub but your code under test calls the stub incorrectly, it can sometimes be difficult to immediately figure out what went wrong. This warning exists to alert you if:
 
--   A mock has at least 1 stubbing configured with [decoy.Decoy.when][]
--   A call was made to the mock that didn't match any configured stubbing
+- A mock has at least 1 stubbing configured with [decoy.Decoy.when][]
+- A call was made to the mock that didn't match any configured stubbing
 
 In the example below, our test subject is supposed to call a `DataGetter` dependency and pass the output data into a `DataHandler` dependency to get the result. However, in writing `Subject.get_and_handle_data`, we forgot to pass `data_id` into `DataGetter.get`.
 
@@ -200,27 +200,3 @@ spy(val="world")            # ok
 spy(wrong_name="ah!")       # triggers an IncorrectCallWarning
 spy("too", "many", "args")  # triggers an IncorrectCallWarning
 ```
-
-### MissingSpecAttributeWarning
-
-If you provide a Decoy mock with a specification `cls` or `func` and you attempt to access an attribute of the mock that does not exist on the specification, Decoy will raise a [decoy.warnings.MissingSpecAttributeWarning][].
-
-While Decoy will merely issue a warning, this call would likely cause the Python engine to error at runtime and should not be ignored. In the next major version of Decoy, this warning will become an error.
-
-```python
-class SomeClass:
-    def foo(self, val: str) -> str:
-        ...
-
-def some_func(val: string) -> int:
-    ...
-
-class_spy = decoy.mock(cls=SomeClass)
-func_spy = decoy.mock(func=some_func)
-
-class_spy.foo("hello")  # ok
-class_spy.bar("world")  # triggers a MissingSpecAttributeWarning
-
-func_spy("hello")       # ok
-func_spy.foo("world")   # triggers a MissingSpecAttributeWarning
-```

tests/test_spy_core.py

@@ -2,11 +2,10 @@
 
 import pytest
 import inspect
-import warnings
 from typing import Any, Dict, NamedTuple, Optional, Tuple, Type
 
 from decoy.spy_core import SpyCore, BoundArgs
-from decoy.warnings import IncorrectCallWarning, MissingSpecAttributeWarning
+from decoy.warnings import IncorrectCallWarning
 from .fixtures import (
     SomeClass,
     SomeAsyncClass,
@@ -151,6 +150,14 @@ class GetSignatureSpec(NamedTuple):
             ),
             expected_signature=None,
         ),
+        GetSignatureSpec(
+            subject=(
+                SpyCore(source=SomeNestedClass, name=None)
+                .create_child_core("union_child", is_async=False)
+                .create_child_core("foo", is_async=False)
+            ),
+            expected_signature=None,
+        ),
         GetSignatureSpec(
             subject=(
                 SpyCore(source=SomeNestedClass, name=None)
@@ -256,6 +263,40 @@ class GetSignatureSpec(NamedTuple):
                 return_annotation=None,
             ),
         ),
+        GetSignatureSpec(
+            subject=(
+                SpyCore(source=SomeNestedClass, name=None)
+                .create_child_core("optional_child", is_async=False)
+                .create_child_core("foo", is_async=False)
+            ),
+            expected_signature=inspect.Signature(
+                parameters=[
+                    inspect.Parameter(
+                        name="val",
+                        kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
+                        annotation=str,
+                    )
+                ],
+                return_annotation=str,
+            ),
+        ),
+        GetSignatureSpec(
+            subject=(
+                SpyCore(source=SomeNestedClass, name=None)
+                .create_child_core("union_none_child", is_async=False)
+                .create_child_core("foo", is_async=False)
+            ),
+            expected_signature=inspect.Signature(
+                parameters=[
+                    inspect.Parameter(
+                        name="val",
+                        kind=inspect.Parameter.POSITIONAL_OR_KEYWORD,
+                        annotation=str,
+                    )
+                ],
+                return_annotation=str,
+            ),
+        ),
     ],
 )
 def test_get_signature(
@@ -440,70 +481,3 @@ def test_warn_if_called_incorrectly() -> None:
 
     with pytest.warns(IncorrectCallWarning, match="missing a required argument"):
         subject.bind_args(wrong_arg_name="1")
-
-
-def test_warn_if_spec_does_not_have_method() -> None:
-    """It should trigger a warning if bound_args is called incorrectly."""
-    class_subject = SpyCore(source=SomeClass, name=None)
-    nested_class_subject = SpyCore(source=SomeNestedClass, name=None)
-    func_subject = SpyCore(source=some_func, name=None)
-    specless_subject = SpyCore(source=None, name="anonymous")
-
-    # specless mocks and correct usage should not warn
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        specless_subject.create_child_core("foo", False)
-
-    # proper class usage should not warn
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        class_subject.create_child_core("foo", False)
-
-    # property access without types should not warn
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        class_subject.create_child_core("mystery_property", False)
-
-    # property access should be allowed through optionals
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        parent = nested_class_subject.create_child_core("optional_child", False)
-        parent.create_child_core("primitive_property", False)
-
-    # property access should be allowed through None unions
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        parent = nested_class_subject.create_child_core("union_none_child", False)
-        parent.create_child_core("primitive_property", False)
-
-    # property access should not be checked through unions
-    with warnings.catch_warnings():
-        warnings.simplefilter("error")
-        parent = nested_class_subject.create_child_core("union_child", False)
-        parent.create_child_core("who_knows", False)
-
-    # incorrect class usage should warn
-    with pytest.warns(
-        MissingSpecAttributeWarning, match="has no attribute 'this_is_wrong'"
-    ):
-        class_subject.create_child_core("this_is_wrong", False)
-
-    # incorrect function usage should warn
-    with pytest.warns(
-        MissingSpecAttributeWarning, match="has no attribute 'this_is_wrong'"
-    ):
-        func_subject.create_child_core("this_is_wrong", False)
-
-    # incorrect nested property usage should warn
-    with pytest.warns(
-        MissingSpecAttributeWarning, match="has no attribute 'this_is_wrong'"
-    ):
-        parent = nested_class_subject.create_child_core("optional_child", False)
-        parent.create_child_core("this_is_wrong", False)
-
-    # incorrect nested property usage should warn
-    with pytest.warns(
-        MissingSpecAttributeWarning, match="has no attribute 'this_is_wrong'"
-    ):
-        parent = nested_class_subject.create_child_core("union_none_child", False)
-        parent.create_child_core("this_is_wrong", False)