Mock Jwt Support should accept a fully-configured Jwt

[jzheaux]

A tester can configure a mock request with a Jwt like so:

this.mvc.perform(get("/")
    .with(jwt()))
// ...

Or like so:

this.mvc.perform(get("/")
    .with(jwt(jwt -> jwt.subject("sub"))))
// ...

It'd be nice to also accept a fully-configured Jwt:

Jwt jwt = // ...
this.mvc.perform(get("/")
    .with(jwt(jwt)))
// ...

Both on the servlet side as well as the reactive side:

Jwt jwt = // ...
this.client
    .mutateWith(mockJwt(jwt))
// ...

[sandmannn]

Hi, I would like to pick this up

[jzheaux]

Thanks, @sandmannn! It's yours.

[jzheaux]

@sandmannn how are things coming? Do you have any questions?

[sandmannn]

I think servlet and reactive can be addressed in different PRs. Lets start iterating on servlet part in this PR #6923
What would be the best place to put tests for it? Up to now I found only https://github.com/sandmannn/spring-security/blob/d0f5b428847c1050d38da7d2af98eb2cda6a9b9e/samples/boot/oauth2resourceserver/src/test/java/sample/OAuth2ResourceServerControllerTests.java where the existing jwt() calls are used in mockMvc.perform(get(....).with(jwt())) style, as you specified in original post.

[jzheaux]

I'd recommend placing them in https://github.com/spring-projects/spring-security/blob/master/test/src/test/java/org/springframework/security/test/web/servlet/request/SecurityMockMvcRequestPostProcessorsJwtTests.java