startPos = failure.indexOfStackFrame(0, StackFramePredicate.USER_CODE);
            if (startPos == -1) {
                // No user code in the stack
                return null;
            }
            // Treat Gradle code as the boundary to allow stepping over JDK and Groovy calls
            endPos = failure.indexOfStackFrame(startPos + 1, GRADLE_CODE);
            if (endPos == -1) {

     */
    List<Failure> getCauses();

    /**
     * Returns the index of the first matching frame in the stack trace, or {@code -1} if not found.
     */
    int indexOfStackFrame(int start, StackFramePredicate predicate);

    public List<Failure> getSuppressed() {
        return suppressed;
    }

    @Override
    public List<Failure> getCauses() {
        return causes;
    }

    @Override
    public int indexOfStackFrame(int fromIndex, StackFramePredicate predicate) {
        int size = stackTrace.size();
        for (int i = fromIndex; i < size; i++) {
            if (predicate.test(stackTrace.get(i), getStackTraceRelevance(i))) {

        def failure = Mock(Failure) {
            getStackTrace() >> stack
            getStackTraceRelevance(_) >> StackTraceRelevance.USER_CODE
            indexOfStackFrame(_, _) >> { start, predicate -> stack.findIndexOf(start) { predicate.test(it, StackTraceRelevance.USER_CODE) } }
        }
        def longDisplayName = Describables.of("<long source>")