How to assert that two list contains elements with the same public properties in NUnit?

Question

I want to assert that the elements of two list contains values that I expected, something like:

var foundCollection = fooManager.LoadFoo();
var expectedCollectio         


        

Answer 1

Using Has.All.Matches() works very well for comparing a found collection to the expected collection. However, it is not necessary to define the predicate used by Has.All.Matches() as a separate function. For relatively simple comparisons, the predicate can be included as part of the lambda expression like this.

Assert.That(found, Has.All.Matches(f => 
    expected.Any(e =>
        f.Bar1 == e.Bar1 &&
        f.Bar2 == e.Bar2 &&
        f.Bar3= = e.Bar3)));

Now, while this assertion will ensure that every entry in the found collection also exists in the expected collection, it does not prove the reverse, namely that every entry in the expected collection is contained in the found collection. So, when it is important to know that found and expected contain are semantically equivalent (i.e., they contain the same semantically equivalent entries), we must add an additional assertion.

The simplest choice is to add the following.

Assert.AreEqual(found.Count() == expected.Count());

For those who prefer a bigger hammer, the following assertion could be used instead.

Assert.That(expected, Has.All.Matches(e => 
    found.Any(f =>
        e.Bar1 == f.Bar1 &&
        e.Bar2 == f.Bar2 &&
        e.Bar3= = f.Bar3)));

By using the first assertion above in conjunction with either the second (preferred) or third assertion, we have now proven that the two collections are semantically the same.