nsubstitute received called with specific object argument

Question

I have a class that looks something like this:

public myArguments
{
    public List<string> argNames {get; set;}
}

In my test I'm doing this:

var expectedArgNames = new List<string>();
expectedArgNames.Add("test");

_mockedClass.CheckArgs(Arg.Any<myArguments>()).Returns(1);

_realClass.CheckArgs();

_mockedClass.Received().CheckArgs(Arg.Is<myArguments>(x => x.argNames.Equals(expectedArgNames));

But the test fails with this error message:

NSubstitute.Exceptions.ReceivedCallsException : Expected to receive a call matching:
    CheckArgs(myArguments)
Actually received no matching calls.
Received 1 non-matching call (non-matching arguments indicated with '*' characters):
    CheckArgs(*myArguments*)

I'm guessing it's because of the .Equals() but I'm not sure how to solve it?

Answer 1

In your test, you're comparing a myArguments class with List<string>.

You should either compare the myArguments.argNames with the List<string> or implement the IEquatable<List<string>> in myArguments.

Besides, when you are comparing List<T>, you should use the SequenceEqualsinstead of Equals.

The first option would be:

_mockedClass.Received().CheckArgs(
    Arg.Is<myArguments>(x => x.argNames.SequenceEqual(expectedArgNames)));

The second would be:

public class myArguments : IEquatable<List<string>>
{
    public List<string> argNames { get; set; }

    public bool Equals(List<string> other)
    {
        if (object.ReferenceEquals(argNames, other))
            return true;
        if (object.ReferenceEquals(argNames, null) || object.ReferenceEquals(other, null))
            return false;

        return argNames.SequenceEqual(other);
    }
}