JUnit deferred assertion message creation

Question

I'm using JUnit assertion message to output some debugging information:

assertEquals(debugString, a, b);

Creation of this string is expensive, and I want to create it only if the assertion failed. How can I do this?

Answer 1

This is a bit of a hack, but you can simulate all the asserts yourself using ifs and fail. E.g., instead of:

assertEquals(debugString, a, b);

Your test could have:

if (!a.equals(b)) {
    fail (debugString);
}