def test_unbound() -> None:
class G(Generic[_T]):
pass
with pytest.raises(TypeError):
is_subtype(G, str)
with pytest.raises(TypeError):
is_subtype(str, G)
def test_disjoint() -> None:
class G(Generic[_T]):
pass
class H(Generic[_T]):
pass
class P(G[int], H[str]):
pass
assert is_subtype(P, G[int])
assert is_subtype(P, H[str])
def test_generic_with_normal_base() -> None:
class A:
pass
class B(Generic[_T], A):
pass
assert is_subtype(B[int], A)
def test_covariance() -> None:
class A:
pass
class B(A):
pass
class C(B):
pass
class G(Generic[_Tco]):
pass
class P(G[B]):
pass
assert is_subtype(P, P)
assert is_subtype(P, G[A])
assert is_subtype(P, G[B])
assert not is_subtype(P, G[C])
def test_partial_generic() -> None:
class G(Generic[_T, _U]):
pass
class H(Generic[_T]):
pass
class A(Generic[_T], G[int, _T]):
pass
class B(Generic[_T], A[_T], H[int]):
pass
class C(B[str]):
pass
assert is_subtype(C, B[str])
assert is_subtype(C, A[str])
assert is_subtype(C, G[int, str])
assert is_subtype(C, H[int])
assert is_subtype(B[bool], A[bool])
assert is_subtype(B[bool], H[int])
assert is_subtype(B[bool], G[int, bool])
def test_complex_variance() -> None:
class A:
pass
class B(A):
pass
class C(B):
pass
class R:
pass
class S(R):
pass
class T(S):
pass
class G(Generic[_Tco, _Tcontra]):
pass
class H(Generic[_Tco]):
pass
class P(G[H[B], H[S]]):
pass
assert is_subtype(P, G[H[B], H[S]])
assert is_subtype(P, G[H[A], H[S]])
assert is_subtype(P, G[H[B], H[T]])
assert is_subtype(P, G[H[A], H[T]])
assert not is_subtype(P, G[H[C], H[S]])
assert not is_subtype(P, G[H[B], H[R]])
assert not is_subtype(P, G[H[C], H[R]])
def test_identity() -> None:
assert is_subtype(str, str)