public void Add()
        {
            var(converterIn, converterOut) = _valueFactory.SetupConverter();

            _sut.Add(Regex, converterIn);

            var builder = _sut.AssertSingle(Regex);

            Assert.AreSame(converterOut, builder.ValueConverter);
        }
        public void Add()
        {
            var inputValue    = new ValueBuilder(Mock.Of <IValueBuilder>());
            var expectedValue = new ValueBuilder(Mock.Of <IValueBuilder>());

            _sut.Add(Regex, _ => expectedValue);

            var builder     = _sut.AssertSingle(Regex);
            var actualValue = builder.ValueConverter(inputValue);

            Assert.AreEqual(expectedValue, actualValue);
        }