No API to perform formLogin and logout on webflux

Summary

While SecurityMockMvcRequestBuilders provides APIs to perform a formLogin and logout, there seems to be no equivalent for the reactive stack.

Configuration

My current configuration looks as follow:

    @Before
    public void setup() {
        this.rest = WebTestClient
            .bindToApplicationContext(this.context)
            .apply(springSecurity())
            .configureClient()
            .filter(basicAuthentication())
            .build();
    }

Instead of the basicAuthentication filter, I'd like to use a formAuthentication
Also a Utility to perform a logout is required.

Version

5.0.6.RELEASE

Start by comparing the existing SecurityMockMvcRequestBuilders formLogin and logout APIs with the reactive WebTestClient setup described in the issue. Identify the reactive test-support entry points that expose basicAuthentication, then define equivalent form-login and logout utilities whose behavior can be verified with WebTestClient tests.