def test_id_dict_generate_id():
d = IdDict()
d.add("a")
assert len(d) == 1
assert "a" in d.values()
d.add("a")
assert len(d) == 2
def test_id_dict_is_cautious_about_ids():
tmp = {1: 2, 2: 3}
d = IdDict(tmp)
assert len(d) == 2
d.add("a")
assert len(d) == 3
d.add("a")
assert len(d) == 4
def test_id_dict_refuse_to_reuse_ids():
d = IdDict()
d[0] = "a"
d.add("b")
assert len(d) == 2
assert_raises(KeyError, lambda: d.add("c", 0))
def test_id_dict_raise_error_if_key_is_not_int():
d = IdDict()
assert_raises(KeyError, lambda: d.__setitem__("a", None))
assert_raises(KeyError, lambda: d.setdefault("a", None))
assert_raises(KeyError, lambda: d.add("a", "key"))
