Question

I am using VS 2010, and running my unit tests with NUnit. The following line correctly detects if two lists differ:

        CollectionAssert.AreEqual(expected, actual);

However, I would like a better error message than the following:

Expected and actual are both <System.Collections.Generic.List`1[MyNamespace.MyClass]> with 2 elements
  Values differ at index [0]
  Expected: <MyNamespace.MyClass>
  But was:  <MyNamespace.MyClass>

In MyNamespace.MyClass, I have implemented the following method:

public new string ToString()

I would expect NUnit to output the following:

Expected and actual are both <System.Collections.Generic.List`1[MyNamespace.MyClass]> with 2 elements
  Values differ at index [0]
  Expected: <24 ounces of cold beer>
  But was:  <2.4 ounces of rotten tomatoes>

However, NUnit does not invoke it. What am I missing?

Answer 1

You’ve hidden the method from object instead of overriding it. Use this:

public override string ToString()

Basically NUnit is just calling object.ToString() – which you hadn’t overridden. Unless it specifically looked for a new method with reflection, it wouldn’t find your one – and overriding is the idiomatic way to do this. Was this just a simple mistake, or did you mean to shadow the method for some reason?