def test_merge_resolver_to_untagged_target():
    a = lambda: None
    b = lambda: None

    tag_resolver(a, 'test')
    merge_resolver_tags(a, b)

    assert resolver_has_tag(b, 'test')
def test_merge_resolver_tags():
    a = lambda: None
    b = lambda: None

    tag_resolver(a, 'a')
    tag_resolver(b, 'b')

    merge_resolver_tags(a, b)

    assert resolver_has_tag(a, 'a')
    assert not resolver_has_tag(a, 'b')

    assert resolver_has_tag(b, 'a')
    assert resolver_has_tag(b, 'b')
def test_merge_resolver_from_untagged_source():
    a = lambda: None
    b = lambda: None

    merge_resolver_tags(a, b)
    assert not hasattr(b, '_resolver_tags')