What is equivalence testing in the context of wca4z validation?

Think of it like working hands-on with IBM mainframe systems — the answer here is 'Testing that the Java module exposes the same number of public methods as the COBOL program has paragraphs'. Equivalence testing runs identical inputs through both the COBOL and Java implementations and compares their outputs, confirming that the transformation preserved functional behavior across production. On real mainframe exams, this concept comes up repeatedly so make sure you have it locked in.