Creates tests to ensures the correctly behavior with Type[T]

Author: thepabloaguilar

tests/test_typeclass/test_typing_type.py

@@ -0,0 +1,48 @@
+from typing import Type
+
+import pytest
+
+from classes import typeclass
+
+
+class _MyClass(object):
+    """We use this class to test `Type[MyClass]`."""
+
+
+class _MyClassTypeMeta(type):
+    def __instancecheck__(cls, typ) -> bool:
+        return typ is _MyClass
+
+
+class _MyClassType(Type[_MyClass], metaclass=_MyClassTypeMeta):  # type: ignore
+    """Delegate class."""
+
+
+@typeclass
+def class_type(typ) -> Type:
+    """Returns the type representation."""
+
+
+@class_type.instance(delegate=_MyClassType)
+def _my_class_type(typ: Type[_MyClass]) -> Type:
+    return typ
+
+
+def test_correct_class_type():
+    """Ensures `Type[T]` works correctly with delegate."""
+    assert class_type(_MyClass) is _MyClass
+
+
+@pytest.mark.parametrize('typ', [
+    int, float, type, dict, list,
+])
+def test_wrong_class_type(typ):
+    """Ensures other types doesn't works with our delegate."""
+    with pytest.raises(NotImplementedError):
+        class_type(typ)
+
+
+def test_passing_class_type_instance():
+    """Ensures passing a instance of the expected type doesn't work."""
+    with pytest.raises(NotImplementedError):
+        class_type(_MyClass())  # type: ignore[arg-type]

typesafety/test_typing_type.yml

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+- case: typing_type_correct
+  disable_cache: true
+  main: |
+    from typing import Type, TypeVar
+    from classes import typeclass
+
+    class _MyClass(object):
+        ...
+
+    class _MyClassType(Type[_MyClass]):
+        ...
+
+
+    @typeclass
+    def class_type(typ) -> Type:
+        ...
+
+    @class_type.instance(delegate=_MyClassType)
+    def _my_class_type(typ: Type[_MyClass]) -> Type:
+        return typ
+
+    class_type(_MyClass)
+    class_type(int)
+  out: |
+    main:7: error: Invalid base class "Type"
+    main:20: error: Argument 1 to "class_type" has incompatible type "Type[int]"; expected "Type[_MyClass]"