Wait, why is the ruby example test cases only comments?
This is why I hate accepting code by others when I don't know the language.

Anyone wanna help me make a quick example test case?
Here is the C# example test case as an example:

using NUnit.Framework;

[TestFixture]
public class Tests
{
  [Test]
  public void Test1()
  {
    Assert.AreEqual(-42, Kata.MakeNegative(42));
  }
}

Would this work?

Test.assert_equals(makeNegative(42), -42)

This error can come up if you run test tests but there are no test cases present, which is the case in this kata :D Either hit submit to check if your code passes or create your own test cases

Plenty of people have submitted Ruby solutions, so it most be your code.

I'm having a similar issue.
Output:
Expected: McClane john, instead got: McClane john

My issue was a leading space, which isn't shown in the output.

Show us your code.