assert lastLogLine == "Waiting for changes to input files..."
    }

    private void rebuiltBecauseOfChange() {
        assert changeDetected()
        assert waitingForChangesMessageAppears()
    }

    private boolean changeDetected() {
        logLines[-2] == "Change detected, executing build..." ||
            lastLogLine == "Change detected, executing build..."
    }

        private final ChangeVisitor delegate;
        private boolean changesDetected;

        public ChangeDetectingVisitor(ChangeVisitor delegate) {
            this.delegate = delegate;
        }

        @Override
        public boolean visitChange(Change change) {
            changesDetected = true;
            return delegate.visitChange(change);
        }