ResponseStubbing should accept Suppliers instead of values to unit-test endpoint that can fail

[adarmiento]

A common use-case is the one in which my client implementation attempts multiple times to contact a server, retrying the call in case the server is momentarily unavailable.

I was not able to find a way to create something like this

onRequest()
                .havingMethodEqualTo("GET")
                .havingPathEqualTo("/my/path")
                .respond()
                .withDelay(1, SECONDS)
                .withStatus(() -> incrementAndGet(attemptNumber) >= 3 ? 200 : 503)
                .withBody("{...}")
                .withEncoding(StandardCharsets.UTF_8)
                .withContentType("application/json; charset=UTF-8");

In this example, the withStatus() method would accept a lambda instead of a value, and I can, therefore, use it to unit test my algorithm which retries failure calls.

This behaviour can be made possible by extending the ResponseStubbing interface by letting it receive Java Suppliers instead of actual values. E.g.

    ResponseStubbing withStatus(Supplier<int> statusSupplier);

The concrete implementation would then lazily compute them when returning values to the tester instead of being eagerly filled with setters at creation time