Add regression test for no-member with generic base class

[cdce8p]

Description

Add regression test. This is fixed with the current astroid master branch.

from abc import ABC
from typing import Generic, TypeVar

Anything = TypeVar("Anything")
MoreSpecific = TypeVar("MoreSpecific", str, int)

class A(ABC, Generic[Anything]):
    def a_method(self) -> None:
        print("hello")

class B(A[MoreSpecific]):
    pass

class C(B[str]):
    pass

c = C()
c.a_method()  # should NOT emit no-member error

Type of Changes

	Type
✓	🐛 Bug fix

Related Issue

Closes pylint-dev/astroid#942

[Pierre-Sassoulas]

This can be rebased on master to get astroid 2.5.7.

[coveralls]

Coverage remained the same at 91.832% when pulling ce0d0bd on cdce8p:regression-test-generic-base into 0e51660 on PyCQA:master.