Abstract Test or Contract Test with pytest

test_map_contract.py

import pytest


def square(num):
    return num * num


def recursive_map(f, _list):
    """Recusive map implementation."""
    if not _list:
        return []
    else:
        head, *tail = _list
        h = [f(head)]
        h.extend(recursive_map(f, tail))
        return h


class MapContract(object):
    @pytest.fixture
    def a_map(self):
        raise NotImplementedError('Not Implemented Yet')

    def test_can_handle_small_list(self, a_map):
        assert list(a_map(square, [1,3,4])) == [1, 9, 16]

    def test_can_handle_large_list(self, a_map):
        num = 10000
        assert len(list(a_map(square, range(num)))) == num


class TestSTDLibContract(MapContract):
    @pytest.fixture
    def a_map(self):
        return map


class TestRecursiveMap(MapContract):
    @pytest.fixture
    def a_map(self):
        return recursive_map

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