Clarify documentation on use of @AutoConfigureRestDocs with WebTestClient

[jnizet]

In Spring Boot 2.1.3, the RestDocsWebTestClientConfiguration class is annotated with @ConditionalOnWebApplication(type = Type.REACTIVE).

This, as far as I understand, prevents the usage of an autoconfigured WebTestClient to document an MVC app, which is strange since you can use WebTestClient to test an MVC app.

[wilkinsona]

since you can use WebTestClient to test an MVC app.

My understanding is that you can only use WebTestClient to test an MVC app if you start an embedded server and use HTTP. In other words, using mocked requests and responses is only supported when testing a WebFlux app.

Given a choice between testing an MVC app using MockMvc with no need for a server and using WebTestClient and requiring an embedded container, I would choose the former. I also think that's what we should encourage users to do, hence things being the way they are just now. Perhaps I'm unusual and we should leave the door open to using WebTestClient with HTTP to test an MVC app.

@jnizet Does my understanding of the situation match yours? Is your preference to use WebTestClient over HTTP to test your MVC app?

[jnizet]

Sure, sorry for the noise.

I'm not very experienced with WebFlux, and missed the WebFluxTest annotation. So I had the feeling that WebTestClient was always used to create integration tests with an embedded server and HTTP, and thus that using MVC or WebFlux wouldn't make a difference.

Now I'm starting to realize that the AutoConfigureRestDocs annotation is usable

• in a @WebMvcTest-annotated test, to test an MVC controller using a mock MVC context, with the help of au autowired MockMvc
• in a @WebFluxTest-annotated test, to test a Webflux controller using a mock WebFlux context, with the help of an autowired WebTestClient
• in a test based on RestAssured, to test an app over HTTP, in order to automatically provide an autowirable documentation spec to the test

WebTestClient can be also be used in @SpringBootTest tests to test an app over HTTP, but then AutoConfigureRestDocs is of no help: the WebTestClient must be configured explicitly, as shown in the Spring REST docs user guide.

To answer your final question: no, my preference is to use sliced tests, using MockMvc, to test and document my MVC apps.
But if I had to write actual integration tests, testing the actual app over HTTP, I guess I would use WebTestClient.

[wilkinsona]

Thanks. Let's use this issue to improve the documentation. It sounds like we need to make it clearer when @AutoConfigureRestDocs can be used and when you'd want to configure the WebTestClient yourself.