public void Constructor_WithoutValue_ExpectedValues(int numberOfDecimalPlaces) { // Call var roundedDouble = new RoundedDouble(numberOfDecimalPlaces); // Assert Assert.IsInstanceOf <IEquatable <RoundedDouble> >(roundedDouble); Assert.IsInstanceOf <IEquatable <double> >(roundedDouble); Assert.IsInstanceOf <IFormattable>(roundedDouble); Assert.IsInstanceOf <IComparable>(roundedDouble); Assert.IsInstanceOf <IComparable <RoundedDouble> >(roundedDouble); Assert.IsInstanceOf <IComparable <double> >(roundedDouble); Assert.AreEqual(numberOfDecimalPlaces, roundedDouble.NumberOfDecimalPlaces); Assert.AreEqual(0.0, roundedDouble.Value); TypeConverterAttribute[] typeAttributes = roundedDouble.GetType().GetCustomAttributes(typeof(TypeConverterAttribute), false) .Cast <TypeConverterAttribute>() .ToArray(); Assert.AreEqual(1, typeAttributes.Length); Assert.AreEqual(new TypeConverterAttribute(typeof(RoundedDoubleConverter)), typeAttributes[0]); }