UnitTest Assertion on a stringc

Hi, I need to assert that a string is a certain value.

d $$$AssertEquals("String value", "Value expected", "Should return correct value")

When running this I get an INVALID OREF error.

Is there any Assertion method I can use where the first parameter can be string like above, rather than an instance of a class as I can see on the documentation?

Thanks,

Andy.