public void Process_Exact()
    {
        var numeral = new NumeralBand(10, "X", _negatedBy.Object);

        _negatedBy.Setup(x => x.Value).Returns(1);
        _negatedBy.Setup(x => x.Numeral).Returns("I");
        numeral.Process(10, _stringBuilder);
        Assert.Equal("X", _stringBuilder.ToString());
        _nextBand.Verify(x => x.Process(It.IsAny <int>(), It.IsAny <StringBuilder>()), Times.Never);
    }
    public void Process_NegateAndContinue()
    {
        var numeral = new NumeralBand(50, "L", _negatedBy.Object);

        numeral.ConfigureNext(_nextBand.Object);
        _negatedBy.Setup(x => x.Value).Returns(10);
        _negatedBy.Setup(x => x.Numeral).Returns("X");
        numeral.Process(54, _stringBuilder);
        Assert.Equal("L", _stringBuilder.ToString());
        _nextBand.Verify(x => x.Process(4, _stringBuilder), Times.Once);
    }