def test_delete_removes_only_given_key():
    skip_list = SkipList()

    skip_list.insert("Key1", 12)
    skip_list.insert("V", 13)
    skip_list.insert("X", 14)
    skip_list.insert("Key2", 15)

    skip_list.delete("V")
    assert skip_list.find("V") is None
    assert skip_list.find("X") == 14
    assert skip_list.find("Key1") == 12
    assert skip_list.find("Key2") == 15

    skip_list.delete("X")
    assert skip_list.find("V") is None
    assert skip_list.find("X") is None
    assert skip_list.find("Key1") == 12
    assert skip_list.find("Key2") == 15

    skip_list.delete("Key1")
    assert skip_list.find("V") is None
    assert skip_list.find("X") is None
    assert skip_list.find("Key1") is None
    assert skip_list.find("Key2") == 15

    skip_list.delete("Key2")
    assert skip_list.find("V") is None
    assert skip_list.find("X") is None
    assert skip_list.find("Key1") is None
    assert skip_list.find("Key2") is None