@Override
        public void connectFailed(SessionProtocol protocol, Endpoint endpoint,
                                  SocketAddress sa, Throwable throwable) {
            try {
                inner.connectFailed(protocol, endpoint, sa, throwable);
            } catch (AssertionError e) {
                result.set(false);
                throw e;
            }
        }
This test class ensures the test fails when an assertion in the callback fails.
core/src/test/java/com/linecorp/armeria/client/proxy/ProxyClientIntegrationTest.java