How to simulate timeout in response to a Rest request in Spring?

user_3127111 0
Viewed 4236

I have a Rest API implemented with Spring Boot 2. To check some client behavior on timeout, how can I simulate that condition in my testing environment? The server should regularly receive the request and process it (in fact, in production timeouts happen due to random network slowdowns and large big response payloads).

Would adding a long sleep be the proper simulation technique? Is there any better method to really have the server "drop" the response?

spring-boot timeout rest spring java
3 Answers

Needing sleeps to test your code is considered bad practice. Instead you want to replicate the exception you receive from the timeout, e.g. java.net.SocketTimeoutException when using RestTemplate.exchange.

Then you can write a test as such:

public class FooTest

    @Mock
    RestTemplate restTemplate;

    @Before
    public void setup(){
        when(restTemplate.exchange(...)).thenThrow(new java.net.SocketTimeoutException())
    }

    @Test
    public void test(){
        // TODO
    }

}

That way you wont be twiddling your thumbs waiting for something to happen.

user_40332920

Sleep is one way to do it, but if you're writing dozens of tests like that then having to wait for a sleep will create a really long-running test suite.

The alternative would be to change the 'threshold' for timeout on the client side for testing. If in production your client is supposed to wait 5 seconds for a response, then in test change it to 0.5 seconds (assuming your server takes longer than that to respond) but keeping the same error handling logic.

The latter might not work in all scenarios, but it will definitely save you from having a test suite that takes 10+ mins to run.

user_135976750

You can do one thing which I did in my case . Actually in my case, when my application is running in a production environment, we keep on polling trades from the API and sometimes it drops the connection by throwing an Exception SSLProtocolException.

What we did

int retryCount =5; 
while (true ){ 
    count++;
    try{ 
        //send an api request here
    }catch (Exception e){
         if(retryCount == count ) {
            throw e
            // here we can do a thread sleep. and try after that period to reconnect 
         }
    }
}

Similarly in your case some Exception it will throw catch that Exception and put your thread in Sleep for a while and after that again try for Connection the retryCount you can modify as per your requirment, in my case it was 5.

user_119310660
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