public void Not_Throw_If_Alias_Doesnt_Exist_When_Looking_Up()
        {
            // arrange
            var repo = new AliasRepository();

            // act
            // assert
            repo.Lookup("whatever").Should().BeEmpty();
        }
        public void Return_All_Commands_That_Match_Alias()
        {
            // arrange
            var repo = new AliasRepository();

            // act
            repo.SetAlias("1", "a");
            repo.SetAlias("2", "a");

            // assert
            repo.Lookup("a").Should().BeEquivalentTo("1 2".Split(' '));
        }