@SpringBootTest and autowiring MockMvc (#2)

[chrylis]

This is a followup to #6008. While the resolution to that added a note to the @WebMvcTest section, the place I as a user was rereading was section 40.3, describing "You can use the webEnvironment attribute". Additionally, the Javadoc for WebEnvironment suggests that the default behavior of @SpringBootTest, with no parameters or extra configuration, is to generate a MockMvc setup if the Servlet API is on the classpath. Adding @WebMvcTest results in a bootstrapper conflict.

From a pragmatic/performance standpoint, not-Web-by-default probably makes sense, but carrying the WebEnvironment on the @SpringBootTest annotation implies that that annotation is sufficient to kick off a Web environment. Since it is not, both the main doc section on @SpringBootTest and the Javadoc should note that, and I'd like to suggest adding a boolean flag to @SpringBootTest to invoke the same effect as adding @AutoConfigureMockMvc or otherwise clarifying the annotation's API to make the additional requirement logically visible from the source.

[wilkinsona]

Additionally, the Javadoc for WebEnvironment suggests that the default behavior of @SpringBootTest, with no parameters or extra configuration, is to generate a MockMvc setup if the Servlet API is on the classpath

It sounds like you're confusing a mock servlet environment – which is the term used in the javadoc – with MockMvc. The latter can be used to test a web application that's running in the former.

From a pragmatic/performance standpoint, not-Web-by-default probably makes sense, but carrying the WebEnvironment on the @SpringBootTest annotation implies that that annotation is sufficient to kick off a Web environment.

It is sufficient and that is exactly what happens. For example, anything that is @ConditionalOnWebApplication will be active.

Perhaps we could avoid some of the confusion by updating the description of MOCK in section 40.3 to mention that it can be used in conjunction with @AutoConfigureMockMvc if you want to use MockMvc for testing?

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[kpdonn]

I was confused by this in the same way the other day. Eventually I figured it out because @AutoConfigureMockMvc is documented in the testing section but it took a while. I think there are two reasons it's easy to miss:

1. @AutoConfigureMockMvc is only mentioned in the section of the documentation that is about testing specific slices of an application. I skipped over those sections the first few times I was going through the documentation because I knew I wanted to be testing my full app (minus the overhead of running the real servlet container) instead of just a slice.
2. It's not clear from the documentation what the point of @SpringBootTest(webEnvironment=WebEnvironment.MOCK) would be if you aren't using MockMvc with it. That made me assume that it would configure it by default. Even now I don't really understand what I would be gaining over @SpringBootTest(webEnvironment=WebEnvironment.NONE) if I wasn't using MockMvc.

I definitely think adding a note in 40.3 MOCK description about needing @AutoConfigureMockMvc to use MockMvc would help a lot.

[wilkinsona]

Even now I don't really understand what I would be gaining over @SpringBootTest(webEnvironment=WebEnvironment.NONE) if I wasn't using MockMvc.

Any beans that are @ConditionalOnWebApplication will not be created if you use WebEnvironment.NONE