im-server/gradle/test.gradle

test {
    def outputReporter = new OutputReporter()
    addTestListener(outputReporter)
    addTestOutputListener(outputReporter)
}

class OutputReporter implements TestListener, TestOutputListener {

    private StringBuilder stdout = new StringBuilder();
    private StringBuilder stderr = new StringBuilder();

    @Override
    void beforeSuite(TestDescriptor suite) {

    }

    @Override
    void afterSuite(TestDescriptor suite, TestResult result) {

    }

    @Override
    void beforeTest(TestDescriptor testDescriptor) {
        if (!testDescriptor.isComposite()) {
            stdout.setLength(0);
            stderr.setLength(0);
        }
    }

    @Override
    void afterTest(TestDescriptor testDescriptor, TestResult result) {
        if (!testDescriptor.isComposite() && result.getResultType() == TestResult.ResultType.FAILURE) {
            if (stdout.length() != 0) {
                println ""
                println "--- STDOUT ---"
                print stdout
                println "--- STDOUT ---"
            }

            if (stderr.length() != 0) {
                println ""
                println "--- STDERR ---"
                println stderr
                println "--- STDERR ---"
            }

        }
    }

    @Override
    void onOutput(TestDescriptor testDescriptor, TestOutputEvent outputEvent) {
        if (!testDescriptor.isComposite()) {
            def buffer = (outputEvent.getDestination() == TestOutputEvent.Destination.StdOut) ? stdout : stderr;
            buffer.append(outputEvent.getMessage());
            if (outputEvent.getMessage().contains("LEAK:")) {
                println stdout
                println stderr
                throw new RuntimeException("Netty ResourceLeakDetector");
            }
        }
    }
}