public async Task ShouldReturnFailedResult_Because_TeachersNotFound()
    {
        var command = new FindTeacherCommand(GetNarfuApi(0));
        var text    = $"{command.Aliases[0]} Петров Пётр Петрович";
        var message = GenerateMessage(DefaultUser.Id, DefaultUser.Id, text);

        var result = await command.Execute(message, DefaultUser);

        result.Should().BeOfType <FailedResult>();
        result.Message.Should().NotBeNullOrEmpty();
        result.Keyboard.Should().BeNull();
    }
    public async Task ShouldReturnSuccessfulResult()
    {
        var command = new FindTeacherCommand(GetNarfuApi());
        var text    = $"{command.Aliases[0]} Иванов Иван Иванович";
        var message = GenerateMessage(DefaultUser.Id, DefaultUser.Id, text);

        var result = await command.Execute(message, DefaultUser);

        result.Should().BeOfType <SuccessfulResult>();
        result.Message.Should().NotBeNullOrEmpty();
        result.Keyboard.Should().NotBeNull();
        result.Keyboard.Buttons.Should().HaveCount(4);
    }