NUnit doesn't work well with Assert.AreEqual

Question

I\'m new to unit testing and NUit in particular. I\'m just typing some examples from the book which refers to Java and JUnit. But I\'m using C# instead.

The problem

Answer 1

The problem is you're hiding Equals, not overriding it. Well done - your unit test has found a bug :)

Your code should be:

public override bool Equals(object obj)
{
    Money money = obj as Money;
    if (money == null)
        return false;

    return (amount == money.amount && currency == money.currency);
}

(This will prevent it from throwing an exception if you give it the wrong type, too.)

I've made the string equality test simpler too - operator overloading can be very helpful :)

By the way, you almost certainly want to:

• Change Currency to be a property, not a method
• Add an Amount property
• Probably change the type of amount to be decimal instead of int
• Make the fields private and readonly
• Seal the class
• Add operator overloads for == and !=
• Possibly add a * operator overload to do the same as Times
• Avoid string formatting when calculating the hash (there are dozens of answers showing better hash implementations)

EDIT: I've just reread that you're using an example from a book. Does the book really hide instead of overriding the Equals method? I suggest you get a new book, if so (unless it's being a deliberate example of when it's wrong to use hiding!)... which book is it?