The expected value was already the first parameter of Assert.AreEqual in C#.

Although, it might be a good idea to move the empty string test out of the random tests, into its individual test case, to avoid confusion?

Yes, this is true. I will try to address this issue.

Can you show a screenshot of such incorrect test? I cannot reproduce the issue, both of your solutions consistently pass for me.

Too late to change specs. It is a custom, simple pig latin kata, leave it as it is.