MockRestServiceServerBuilder cannot be cached [SPR-14306]

[spring-projects-issues]

Stéphane Nicoll opened SPR-14306 and commented

I am investigating the option of adding a @RestClientTest annotation in Spring Boot that would automatically configure a RestTemplate and MockRestServiceServer.

The default expectation managers throw an exception if you try to add a request after you have validated one, something like:

java.lang.IllegalStateException: Cannot add more expectations after actual requests are made.

	at org.springframework.util.Assert.state(Assert.java:392)
	at org.springframework.test.web.client.AbstractRequestExpectationManager.expectRequest(AbstractRequestExpectationManager.java:60)
	at org.springframework.test.web.client.MockRestServiceServer.expect(MockRestServiceServer.java:112)
	at org.springframework.test.web.client.MockRestServiceServer.expect(MockRestServiceServer.java:95)

There is no way to "reset" the mock server at the end of the test so it looks like the only way to make this work is to create a new server instance per test.

My next move was to try to share the builder and simply call build in a Before annotated method but that does not work either as the builder shares an expectation manager by default, which means that every created server using the same builder share the same expectation manager.

Looking at the API, I find it weird that we can both use ignoreExpectOrder and expectationManager as those are mutually exclusive. Perhaps removing the latter and creating a fresh expectation manager would help? It also would be nice if a server instance could be reused for multiple tests with a public reset method that would reset the expectation manager.

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Affects: 4.3 RC2

[spring-projects-issues]

Rossen Stoyanchev commented

We can add a reset method. It has come up before 4.3 but it was never requested.

I find it weird that we can both use ignoreExpectOrder and expectationManager as those are mutually exclusive.

They're mutually exclusive and that's the point. There is an underlying strategy. You get a default implementation, or with ignoreExpectOrder you get a different one, or with expectationManager you can configure a custom one. I don't see anything odd. Perhaps what you are trying to do isn't quite what it's meant for?

[spring-projects-issues]

Stéphane Nicoll commented

My point is that if I set ignoreExpectOrder(true) then expectationManager(myExpectationManager() the first call is ignored. It's not a big deal all things considered but it surprised me the first time I tried. I think the fact that the builder has a state is wrong because if you cache the builder you just can't call build twice in a given test...

[spring-projects-issues]

Rossen Stoyanchev commented

I've changed the builder so it can be re-used to build again. Along with that expectationManager is replaced with an overloaded build method which reflects that fact a new instance is required for each build. Hopefully that irons things out.

[spring-projects-issues]

Rossen Stoyanchev commented

There is a reset() now as well which was the preferred option.