Testing Spring Retry with Feign client

Question

I would like to test retries of Spring Retry that I have added to my Feign client. The problem is that my client looks like this:

@FeignClient(some config)
public interface MyClient {
    @PostMapping(value = "", consumes = APPLICATION_JSON_VALUE, produces = APPLICATION_JSON_VALUE)
    @Retryable(maxAttempts = 3, backoff = @Backoff(multiplier = 2))
    void performACall(@RequestBody someBody);

(other methods)
}

Then when I write @SpringBootTest to test the retries (using Mockito verify() with times()) I can autowire the service using MyClient and inject MyClient as a mock, but that's not what has to be done.

My understanding is that it should be MyClient that's autowired and I should mock some code within it to simulate different behaviours and test the retries.

However since MyClient is just an interface with annotation this cannot be done.

Is there a way I can test the retries in such case?