@Override
        public String toString() {
            StringBuilder builder = new StringBuilder(String.format(
                    "Smithy validation test runner encountered %d successful result(s), and %d failed result(s)",
                    getSuccessCount(),
                    getFailedResults().size()));
            getFailedResults().forEach(failed -> builder.append('\n').append(failed.toString()).append('\n'));
            return builder.toString();
        }
@return Returns the test cases that failed.
smithy-model/src/main/java/software/amazon/smithy/model/validation/testrunner/SmithyTestSuite.java