[[test-webflux]]
= Reactive Test Support

[[test-erms]]
== Testing Reactive Method Security

For example, we can test our example from xref:reactive/method.adoc#jc-erms[] using the same setup and annotations we did in xref:servlet/test/method.adoc#test-method[].
Here is a minimal sample of what we can do:

====
.Java
[source,java,role="primary"]
----
@RunWith(SpringRunner.class)
@ContextConfiguration(classes = HelloWebfluxMethodApplication.class)
public class HelloWorldMessageServiceTests {
	@Autowired
	HelloWorldMessageService messages;

	@Test
	public void messagesWhenNotAuthenticatedThenDenied() {
		StepVerifier.create(this.messages.findMessage())
			.expectError(AccessDeniedException.class)
			.verify();
	}

	@Test
	@WithMockUser
	public void messagesWhenUserThenDenied() {
		StepVerifier.create(this.messages.findMessage())
			.expectError(AccessDeniedException.class)
			.verify();
	}

	@Test
	@WithMockUser(roles = "ADMIN")
	public void messagesWhenAdminThenOk() {
		StepVerifier.create(this.messages.findMessage())
			.expectNext("Hello World!")
			.verifyComplete();
	}
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@RunWith(SpringRunner::class)
@ContextConfiguration(classes = [HelloWebfluxMethodApplication::class])
class HelloWorldMessageServiceTests {
    @Autowired
    lateinit var messages: HelloWorldMessageService

    @Test
    fun messagesWhenNotAuthenticatedThenDenied() {
        StepVerifier.create(messages.findMessage())
            .expectError(AccessDeniedException::class.java)
            .verify()
    }

    @Test
    @WithMockUser
    fun messagesWhenUserThenDenied() {
        StepVerifier.create(messages.findMessage())
            .expectError(AccessDeniedException::class.java)
            .verify()
    }

    @Test
    @WithMockUser(roles = ["ADMIN"])
    fun messagesWhenAdminThenOk() {
        StepVerifier.create(messages.findMessage())
            .expectNext("Hello World!")
            .verifyComplete()
    }
}
----
====

[[test-webtestclient]]
== WebTestClientSupport

Spring Security provides integration with `WebTestClient`.
The basic setup looks like this:

[source,java]
----
@RunWith(SpringRunner.class)
@ContextConfiguration(classes = HelloWebfluxMethodApplication.class)
public class HelloWebfluxMethodApplicationTests {
	@Autowired
	ApplicationContext context;

	WebTestClient rest;

	@Before
	public void setup() {
		this.rest = WebTestClient
			.bindToApplicationContext(this.context)
			// add Spring Security test Support
			.apply(springSecurity())
			.configureClient()
			.filter(basicAuthentication())
			.build();
	}
	// ...
}
----

=== Authentication

After applying the Spring Security support to `WebTestClient` we can use either annotations or `mutateWith` support.
For example:

====
.Java
[source,java,role="primary"]
----
@Test
public void messageWhenNotAuthenticated() throws Exception {
	this.rest
		.get()
		.uri("/message")
		.exchange()
		.expectStatus().isUnauthorized();
}

// --- WithMockUser ---

@Test
@WithMockUser
public void messageWhenWithMockUserThenForbidden() throws Exception {
	this.rest
		.get()
		.uri("/message")
		.exchange()
		.expectStatus().isEqualTo(HttpStatus.FORBIDDEN);
}

@Test
@WithMockUser(roles = "ADMIN")
public void messageWhenWithMockAdminThenOk() throws Exception {
	this.rest
		.get()
		.uri("/message")
		.exchange()
		.expectStatus().isOk()
		.expectBody(String.class).isEqualTo("Hello World!");
}

// --- mutateWith mockUser ---

@Test
public void messageWhenMutateWithMockUserThenForbidden() throws Exception {
	this.rest
		.mutateWith(mockUser())
		.get()
		.uri("/message")
		.exchange()
		.expectStatus().isEqualTo(HttpStatus.FORBIDDEN);
}

@Test
public void messageWhenMutateWithMockAdminThenOk() throws Exception {
	this.rest
		.mutateWith(mockUser().roles("ADMIN"))
		.get()
		.uri("/message")
		.exchange()
		.expectStatus().isOk()
		.expectBody(String.class).isEqualTo("Hello World!");
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
import org.springframework.test.web.reactive.server.expectBody

//...

@Test
@WithMockUser
fun messageWhenWithMockUserThenForbidden() {
    this.rest.get().uri("/message")
        .exchange()
        .expectStatus().isEqualTo(HttpStatus.FORBIDDEN)
}

@Test
@WithMockUser(roles = ["ADMIN"])
fun messageWhenWithMockAdminThenOk() {
    this.rest.get().uri("/message")
        .exchange()
        .expectStatus().isOk
        .expectBody<String>().isEqualTo("Hello World!")

}

// --- mutateWith mockUser ---

@Test
fun messageWhenMutateWithMockUserThenForbidden() {
    this.rest
        .mutateWith(mockUser())
        .get().uri("/message")
        .exchange()
        .expectStatus().isEqualTo(HttpStatus.FORBIDDEN)
}

@Test
fun messageWhenMutateWithMockAdminThenOk() {
    this.rest
        .mutateWith(mockUser().roles("ADMIN"))
        .get().uri("/message")
        .exchange()
        .expectStatus().isOk
        .expectBody<String>().isEqualTo("Hello World!")
}
----
====


=== CSRF Support

Spring Security also provides support for CSRF testing with `WebTestClient`.
For example:

====
.Java
[source,java,role="primary"]
----
this.rest
	// provide a valid CSRF token
	.mutateWith(csrf())
	.post()
	.uri("/login")
	...
----

.Kotlin
[source,kotlin,role="secondary"]
----
this.rest
    // provide a valid CSRF token
    .mutateWith(csrf())
    .post()
    .uri("/login")
    ...
----
====

[[webflux-testing-oauth2]]
=== Testing OAuth 2.0

When it comes to OAuth 2.0, the same principles covered earlier still apply: Ultimately, it depends on what your method under test is expecting to be in the `SecurityContextHolder`.

For example, for a controller that looks like this:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(Principal user) {
    return Mono.just(user.getName());
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(user: Principal): Mono<String> {
    return Mono.just(user.name)
}
----
====

There's nothing OAuth2-specific about it, so you will likely be able to simply <<test-erms,use `@WithMockUser`>> and be fine.

But, in cases where your controllers are bound to some aspect of Spring Security's OAuth 2.0 support, like the following:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@AuthenticationPrincipal OidcUser user) {
    return Mono.just(user.getIdToken().getSubject());
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(@AuthenticationPrincipal user: OidcUser): Mono<String> {
    return Mono.just(user.idToken.subject)
}
----
====

then Spring Security's test support can come in handy.

[[webflux-testing-oidc-login]]
=== Testing OIDC Login

Testing the method above with `WebTestClient` would require simulating some kind of grant flow with an authorization server.
Certainly this would be a daunting task, which is why Spring Security ships with support for removing this boilerplate.

For example, we can tell Spring Security to include a default `OidcUser` using the `SecurityMockServerConfigurers#mockOidcLogin` method, like so:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOidcLogin()).get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOidcLogin())
    .get().uri("/endpoint")
    .exchange()
----
====

What this will do is configure the associated `MockServerRequest` with an `OidcUser` that includes a simple `OidcIdToken`, `OidcUserInfo`, and `Collection` of granted authorities.

Specifically, it will include an `OidcIdToken` with a `sub` claim set to `user`:

====
.Java
[source,java,role="primary"]
----
assertThat(user.getIdToken().getClaim("sub")).isEqualTo("user");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(user.idToken.getClaim<String>("sub")).isEqualTo("user")
----
====

an `OidcUserInfo` with no claims set:

====
.Java
[source,java,role="primary"]
----
assertThat(user.getUserInfo().getClaims()).isEmpty();
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(user.userInfo.claims).isEmpty()
----
====

and a `Collection` of authorities with just one authority, `SCOPE_read`:

====
.Java
[source,java,role="primary"]
----
assertThat(user.getAuthorities()).hasSize(1);
assertThat(user.getAuthorities()).containsExactly(new SimpleGrantedAuthority("SCOPE_read"));
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(user.authorities).hasSize(1)
assertThat(user.authorities).containsExactly(SimpleGrantedAuthority("SCOPE_read"))
----
====

Spring Security does the necessary work to make sure that the `OidcUser` instance is available for xref:servlet/integrations/mvc.adoc#mvc-authentication-principal[the `@AuthenticationPrincipal` annotation].

Further, it also links that `OidcUser` to a simple instance of `OAuth2AuthorizedClient` that it deposits into a mock `ServerOAuth2AuthorizedClientRepository`.
This can be handy if your tests <<webflux-testing-oauth2-client,use the `@RegisteredOAuth2AuthorizedClient` annotation>>..

[[webflux-testing-oidc-login-authorities]]
==== Configuring Authorities

In many circumstances, your method is protected by filter or method security and needs your `Authentication` to have certain granted authorities to allow the request.

In this case, you can supply what granted authorities you need using the `authorities()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOidcLogin()
        .authorities(new SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOidcLogin()
        .authorities(SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oidc-login-claims]]
==== Configuring Claims

And while granted authorities are quite common across all of Spring Security, we also have claims in the case of OAuth 2.0.

Let's say, for example, that you've got a `user_id` claim that indicates the user's id in your system.
You might access it like so in a controller:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@AuthenticationPrincipal OidcUser oidcUser) {
    String userId = oidcUser.getIdToken().getClaim("user_id");
    // ...
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(@AuthenticationPrincipal oidcUser: OidcUser): Mono<String> {
    val userId = oidcUser.idToken.getClaim<String>("user_id")
    // ...
}
----
====

In that case, you'd want to specify that claim with the `idToken()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOidcLogin()
        .idToken(token -> token.claim("user_id", "1234"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOidcLogin()
        .idToken { token -> token.claim("user_id", "1234") }
    )
    .get().uri("/endpoint").exchange()
----
====

since `OidcUser` collects its claims from `OidcIdToken`.

[[webflux-testing-oidc-login-user]]
==== Additional Configurations

There are additional methods, too, for further configuring the authentication; it simply depends on what data your controller expects:

* `userInfo(OidcUserInfo.Builder)` - For configuring the `OidcUserInfo` instance
* `clientRegistration(ClientRegistration)` - For configuring the associated `OAuth2AuthorizedClient` with a given `ClientRegistration`
* `oidcUser(OidcUser)` - For configuring the complete `OidcUser` instance

That last one is handy if you:
1. Have your own implementation of `OidcUser`, or
2. Need to change the name attribute

For example, let's say that your authorization server sends the principal name in the `user_name` claim instead of the `sub` claim.
In that case, you can configure an `OidcUser` by hand:

====
.Java
[source,java,role="primary"]
----
OidcUser oidcUser = new DefaultOidcUser(
        AuthorityUtils.createAuthorityList("SCOPE_message:read"),
        OidcIdToken.withTokenValue("id-token").claim("user_name", "foo_user").build(),
        "user_name");

client
    .mutateWith(mockOidcLogin().oidcUser(oidcUser))
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
val oidcUser: OidcUser = DefaultOidcUser(
    AuthorityUtils.createAuthorityList("SCOPE_message:read"),
    OidcIdToken.withTokenValue("id-token").claim("user_name", "foo_user").build(),
    "user_name"
)

client
    .mutateWith(mockOidcLogin().oidcUser(oidcUser))
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oauth2-login]]
=== Testing OAuth 2.0 Login

As with <<webflux-testing-oidc-login,testing OIDC login>>, testing OAuth 2.0 Login presents a similar challenge of mocking a grant flow.
And because of that, Spring Security also has test support for non-OIDC use cases.

Let's say that we've got a controller that gets the logged-in user as an `OAuth2User`:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@AuthenticationPrincipal OAuth2User oauth2User) {
    return Mono.just(oauth2User.getAttribute("sub"));
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(@AuthenticationPrincipal oauth2User: OAuth2User): Mono<String> {
    return Mono.just(oauth2User.getAttribute("sub"))
}
----
====

In that case, we can tell Spring Security to include a default `OAuth2User` using the `SecurityMockServerConfigurers#mockOAuth2Login` method, like so:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOAuth2Login())
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOAuth2Login())
    .get().uri("/endpoint").exchange()
----
====

What this will do is configure the associated `MockServerRequest` with an `OAuth2User` that includes a simple `Map` of attributes and `Collection` of granted authorities.

Specifically, it will include a `Map` with a key/value pair of `sub`/`user`:

====
.Java
[source,java,role="primary"]
----
assertThat((String) user.getAttribute("sub")).isEqualTo("user");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(user.getAttribute<String>("sub")).isEqualTo("user")
----
====

and a `Collection` of authorities with just one authority, `SCOPE_read`:

====
.Java
[source,java,role="primary"]
----
assertThat(user.getAuthorities()).hasSize(1);
assertThat(user.getAuthorities()).containsExactly(new SimpleGrantedAuthority("SCOPE_read"));
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(user.authorities).hasSize(1)
assertThat(user.authorities).containsExactly(SimpleGrantedAuthority("SCOPE_read"))
----
====

Spring Security does the necessary work to make sure that the `OAuth2User` instance is available for xref:servlet/integrations/mvc.adoc#mvc-authentication-principal[the `@AuthenticationPrincipal` annotation].

Further, it also links that `OAuth2User` to a simple instance of `OAuth2AuthorizedClient` that it deposits in a mock `ServerOAuth2AuthorizedClientRepository`.
This can be handy if your tests <<webflux-testing-oauth2-client,use the `@RegisteredOAuth2AuthorizedClient` annotation>>.

[[webflux-testing-oauth2-login-authorities]]
==== Configuring Authorities

In many circumstances, your method is protected by filter or method security and needs your `Authentication` to have certain granted authorities to allow the request.

In this case, you can supply what granted authorities you need using the `authorities()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOAuth2Login()
        .authorities(new SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOAuth2Login()
        .authorities(SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oauth2-login-claims]]
==== Configuring Claims

And while granted authorities are quite common across all of Spring Security, we also have claims in the case of OAuth 2.0.

Let's say, for example, that you've got a `user_id` attribute that indicates the user's id in your system.
You might access it like so in a controller:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@AuthenticationPrincipal OAuth2User oauth2User) {
    String userId = oauth2User.getAttribute("user_id");
    // ...
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(@AuthenticationPrincipal oauth2User: OAuth2User): Mono<String> {
    val userId = oauth2User.getAttribute<String>("user_id")
    // ...
}
----
====

In that case, you'd want to specify that attribute with the `attributes()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOAuth2Login()
        .attributes(attrs -> attrs.put("user_id", "1234"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOAuth2Login()
        .attributes { attrs -> attrs["user_id"] = "1234" }
    )
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oauth2-login-user]]
==== Additional Configurations

There are additional methods, too, for further configuring the authentication; it simply depends on what data your controller expects:

* `clientRegistration(ClientRegistration)` - For configuring the associated `OAuth2AuthorizedClient` with a given `ClientRegistration`
* `oauth2User(OAuth2User)` - For configuring the complete `OAuth2User` instance

That last one is handy if you:
1. Have your own implementation of `OAuth2User`, or
2. Need to change the name attribute

For example, let's say that your authorization server sends the principal name in the `user_name` claim instead of the `sub` claim.
In that case, you can configure an `OAuth2User` by hand:

====
.Java
[source,java,role="primary"]
----
OAuth2User oauth2User = new DefaultOAuth2User(
        AuthorityUtils.createAuthorityList("SCOPE_message:read"),
        Collections.singletonMap("user_name", "foo_user"),
        "user_name");

client
    .mutateWith(mockOAuth2Login().oauth2User(oauth2User))
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
val oauth2User: OAuth2User = DefaultOAuth2User(
    AuthorityUtils.createAuthorityList("SCOPE_message:read"),
    mapOf(Pair("user_name", "foo_user")),
    "user_name"
)

client
    .mutateWith(mockOAuth2Login().oauth2User(oauth2User))
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oauth2-client]]
=== Testing OAuth 2.0 Clients

Independent of how your user authenticates, you may have other tokens and client registrations that are in play for the request you are testing.
For example, your controller may be relying on the client credentials grant to get a token that isn't associated with the user at all:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@RegisteredOAuth2AuthorizedClient("my-app") OAuth2AuthorizedClient authorizedClient) {
    return this.webClient.get()
        .attributes(oauth2AuthorizedClient(authorizedClient))
        .retrieve()
        .bodyToMono(String.class);
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
import org.springframework.web.reactive.function.client.bodyToMono

// ...

@GetMapping("/endpoint")
fun foo(@RegisteredOAuth2AuthorizedClient("my-app") authorizedClient: OAuth2AuthorizedClient?): Mono<String> {
    return this.webClient.get()
        .attributes(oauth2AuthorizedClient(authorizedClient))
        .retrieve()
        .bodyToMono()
}
----
====

Simulating this handshake with the authorization server could be cumbersome.
Instead, you can use `SecurityMockServerConfigurers#mockOAuth2Client` to add a `OAuth2AuthorizedClient` into a mock `ServerOAuth2AuthorizedClientRepository`:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOAuth2Client("my-app"))
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOAuth2Client("my-app"))
    .get().uri("/endpoint").exchange()
----
====

What this will do is create an `OAuth2AuthorizedClient` that has a simple `ClientRegistration`, `OAuth2AccessToken`, and resource owner name.

Specifically, it will include a `ClientRegistration` with a client id of "test-client" and client secret of "test-secret":

====
.Java
[source,java,role="primary"]
----
assertThat(authorizedClient.getClientRegistration().getClientId()).isEqualTo("test-client");
assertThat(authorizedClient.getClientRegistration().getClientSecret()).isEqualTo("test-secret");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(authorizedClient.clientRegistration.clientId).isEqualTo("test-client")
assertThat(authorizedClient.clientRegistration.clientSecret).isEqualTo("test-secret")
----
====

a resource owner name of "user":

====
.Java
[source,java,role="primary"]
----
assertThat(authorizedClient.getPrincipalName()).isEqualTo("user");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(authorizedClient.principalName).isEqualTo("user")
----
====

and an `OAuth2AccessToken` with just one scope, `read`:

====
.Java
[source,java,role="primary"]
----
assertThat(authorizedClient.getAccessToken().getScopes()).hasSize(1);
assertThat(authorizedClient.getAccessToken().getScopes()).containsExactly("read");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(authorizedClient.accessToken.scopes).hasSize(1)
assertThat(authorizedClient.accessToken.scopes).containsExactly("read")
----
====

The client can then be retrieved as normal using `@RegisteredOAuth2AuthorizedClient` in a controller method.

[[webflux-testing-oauth2-client-scopes]]
==== Configuring Scopes

In many circumstances, the OAuth 2.0 access token comes with a set of scopes.
If your controller inspects these, say like so:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(@RegisteredOAuth2AuthorizedClient("my-app") OAuth2AuthorizedClient authorizedClient) {
    Set<String> scopes = authorizedClient.getAccessToken().getScopes();
    if (scopes.contains("message:read")) {
        return this.webClient.get()
            .attributes(oauth2AuthorizedClient(authorizedClient))
            .retrieve()
            .bodyToMono(String.class);
    }
    // ...
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
import org.springframework.web.reactive.function.client.bodyToMono

// ...

@GetMapping("/endpoint")
fun foo(@RegisteredOAuth2AuthorizedClient("my-app") authorizedClient: OAuth2AuthorizedClient): Mono<String> {
    val scopes = authorizedClient.accessToken.scopes
    if (scopes.contains("message:read")) {
        return webClient.get()
            .attributes(oauth2AuthorizedClient(authorizedClient))
            .retrieve()
            .bodyToMono()
    }
    // ...
}
----
====

then you can configure the scope using the `accessToken()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOAuth2Client("my-app")
        .accessToken(new OAuth2AccessToken(BEARER, "token", null, null, Collections.singleton("message:read")))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOAuth2Client("my-app")
        .accessToken(OAuth2AccessToken(BEARER, "token", null, null, setOf("message:read")))
)
.get().uri("/endpoint").exchange()
----
====

[[webflux-testing-oauth2-client-registration]]
==== Additional Configurations

There are additional methods, too, for further configuring the authentication; it simply depends on what data your controller expects:

* `principalName(String)` - For configuring the resource owner name
* `clientRegistration(Consumer<ClientRegistration.Builder>)` - For configuring the associated `ClientRegistration`
* `clientRegistration(ClientRegistration)` - For configuring the complete `ClientRegistration`

That last one is handy if you want to use a real `ClientRegistration`

For example, let's say that you are wanting to use one of your app's `ClientRegistration` definitions, as specified in your `application.yml`.

In that case, your test can autowire the `ReactiveClientRegistrationRepository` and look up the one your test needs:

====
.Java
[source,java,role="primary"]
----
@Autowired
ReactiveClientRegistrationRepository clientRegistrationRepository;

// ...

client
    .mutateWith(mockOAuth2Client()
        .clientRegistration(this.clientRegistrationRepository.findByRegistrationId("facebook").block())
    )
    .get().uri("/exchange").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
@Autowired
lateinit var clientRegistrationRepository: ReactiveClientRegistrationRepository

// ...

client
    .mutateWith(mockOAuth2Client()
        .clientRegistration(this.clientRegistrationRepository.findByRegistrationId("facebook").block())
    )
    .get().uri("/exchange").exchange()
----
====

[[webflux-testing-jwt]]
=== Testing JWT Authentication

In order to make an authorized request on a resource server, you need a bearer token.
If your resource server is configured for JWTs, then this would mean that the bearer token needs to be signed and then encoded according to the JWT specification.
All of this can be quite daunting, especially when this isn't the focus of your test.

Fortunately, there are a number of simple ways that you can overcome this difficulty and allow your tests to focus on authorization and not on representing bearer tokens.
We'll look at two of them now:

==== `mockJwt() WebTestClientConfigurer`

The first way is via a `WebTestClientConfigurer`.
The simplest of these would be to use the `SecurityMockServerConfigurers#mockJwt` method like the following:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockJwt()).get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockJwt()).get().uri("/endpoint").exchange()
----
====

What this will do is create a mock `Jwt`, passing it correctly through any authentication APIs so that it's available for your authorization mechanisms to verify.

By default, the `JWT` that it creates has the following characteristics:

[source,json]
----
{
  "headers" : { "alg" : "none" },
  "claims" : {
    "sub" : "user",
    "scope" : "read"
  }
}
----

And the resulting `Jwt`, were it tested, would pass in the following way:

====
.Java
[source,java,role="primary"]
----
assertThat(jwt.getTokenValue()).isEqualTo("token");
assertThat(jwt.getHeaders().get("alg")).isEqualTo("none");
assertThat(jwt.getSubject()).isEqualTo("sub");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(jwt.tokenValue).isEqualTo("token")
assertThat(jwt.headers["alg"]).isEqualTo("none")
assertThat(jwt.subject).isEqualTo("sub")
----
====

These values can, of course be configured.

Any headers or claims can be configured with their corresponding methods:

====
.Java
[source,java,role="primary"]
----
client
	.mutateWith(mockJwt().jwt(jwt -> jwt.header("kid", "one")
		.claim("iss", "https://idp.example.org")))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockJwt().jwt { jwt -> jwt.header("kid", "one")
        .claim("iss", "https://idp.example.org")
    })
    .get().uri("/endpoint").exchange()
----
====

====
.Java
[source,java,role="primary"]
----
client
	.mutateWith(mockJwt().jwt(jwt -> jwt.claims(claims -> claims.remove("scope"))))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockJwt().jwt { jwt ->
        jwt.claims { claims -> claims.remove("scope") }
    })
    .get().uri("/endpoint").exchange()
----
====

The `scope` and `scp` claims are processed the same way here as they are in a normal bearer token request.
However, this can be overridden simply by providing the list of `GrantedAuthority` instances that you need for your test:

====
.Java
[source,java,role="primary"]
----
client
	.mutateWith(mockJwt().authorities(new SimpleGrantedAuthority("SCOPE_messages")))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockJwt().authorities(SimpleGrantedAuthority("SCOPE_messages")))
    .get().uri("/endpoint").exchange()
----
====

Or, if you have a custom `Jwt` to `Collection<GrantedAuthority>` converter, you can also use that to derive the authorities:

====
.Java
[source,java,role="primary"]
----
client
	.mutateWith(mockJwt().authorities(new MyConverter()))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockJwt().authorities(MyConverter()))
    .get().uri("/endpoint").exchange()
----
====

You can also specify a complete `Jwt`, for which `{security-api-url}org/springframework/security/oauth2/jwt/Jwt.Builder.html[Jwt.Builder]` comes quite handy:

====
.Java
[source,java,role="primary"]
----
Jwt jwt = Jwt.withTokenValue("token")
    .header("alg", "none")
    .claim("sub", "user")
    .claim("scope", "read")
    .build();

client
	.mutateWith(mockJwt().jwt(jwt))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
val jwt: Jwt = Jwt.withTokenValue("token")
    .header("alg", "none")
    .claim("sub", "user")
    .claim("scope", "read")
    .build()

client
    .mutateWith(mockJwt().jwt(jwt))
    .get().uri("/endpoint").exchange()
----
====

==== `authentication()` `WebTestClientConfigurer`

The second way is by using the `authentication()` `Mutator`.
Essentially, you can instantiate your own `JwtAuthenticationToken` and provide it in your test, like so:

====
.Java
[source,java,role="primary"]
----
Jwt jwt = Jwt.withTokenValue("token")
    .header("alg", "none")
    .claim("sub", "user")
    .build();
Collection<GrantedAuthority> authorities = AuthorityUtils.createAuthorityList("SCOPE_read");
JwtAuthenticationToken token = new JwtAuthenticationToken(jwt, authorities);

client
	.mutateWith(mockAuthentication(token))
	.get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
val jwt = Jwt.withTokenValue("token")
    .header("alg", "none")
    .claim("sub", "user")
    .build()
val authorities: Collection<GrantedAuthority> = AuthorityUtils.createAuthorityList("SCOPE_read")
val token = JwtAuthenticationToken(jwt, authorities)

client
    .mutateWith(mockAuthentication<JwtMutator>(token))
    .get().uri("/endpoint").exchange()
----
====

Note that as an alternative to these, you can also mock the `ReactiveJwtDecoder` bean itself with a `@MockBean` annotation.

[[webflux-testing-opaque-token]]
=== Testing Opaque Token Authentication

Similar to <<webflux-testing-jwt,JWTs>>, opaque tokens require an authorization server in order to verify their validity, which can make testing more difficult.
To help with that, Spring Security has test support for opaque tokens.

Let's say that we've got a controller that retrieves the authentication as a `BearerTokenAuthentication`:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(BearerTokenAuthentication authentication) {
    return Mono.just((String) authentication.getTokenAttributes().get("sub"));
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(authentication: BearerTokenAuthentication): Mono<String?> {
    return Mono.just(authentication.tokenAttributes["sub"] as String?)
}
----
====

In that case, we can tell Spring Security to include a default `BearerTokenAuthentication` using the `SecurityMockServerConfigurers#mockOpaqueToken` method, like so:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOpaqueToken())
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOpaqueToken())
    .get().uri("/endpoint").exchange()
----
====

What this will do is configure the associated `MockHttpServletRequest` with a `BearerTokenAuthentication` that includes a simple `OAuth2AuthenticatedPrincipal`, `Map` of attributes, and `Collection` of granted authorities.

Specifically, it will include a `Map` with a key/value pair of `sub`/`user`:

====
.Java
[source,java,role="primary"]
----
assertThat((String) token.getTokenAttributes().get("sub")).isEqualTo("user");
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(token.tokenAttributes["sub"] as String?).isEqualTo("user")
----
====

and a `Collection` of authorities with just one authority, `SCOPE_read`:

====
.Java
[source,java,role="primary"]
----
assertThat(token.getAuthorities()).hasSize(1);
assertThat(token.getAuthorities()).containsExactly(new SimpleGrantedAuthority("SCOPE_read"));
----

.Kotlin
[source,kotlin,role="secondary"]
----
assertThat(token.authorities).hasSize(1)
assertThat(token.authorities).containsExactly(SimpleGrantedAuthority("SCOPE_read"))
----
====

Spring Security does the necessary work to make sure that the `BearerTokenAuthentication` instance is available for your controller methods.

[[webflux-testing-opaque-token-authorities]]
==== Configuring Authorities

In many circumstances, your method is protected by filter or method security and needs your `Authentication` to have certain granted authorities to allow the request.

In this case, you can supply what granted authorities you need using the `authorities()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOpaqueToken()
        .authorities(new SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOpaqueToken()
        .authorities(SimpleGrantedAuthority("SCOPE_message:read"))
    )
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-opaque-token-attributes]]
==== Configuring Claims

And while granted authorities are quite common across all of Spring Security, we also have attributes in the case of OAuth 2.0.

Let's say, for example, that you've got a `user_id` attribute that indicates the user's id in your system.
You might access it like so in a controller:

====
.Java
[source,java,role="primary"]
----
@GetMapping("/endpoint")
public Mono<String> foo(BearerTokenAuthentication authentication) {
    String userId = (String) authentication.getTokenAttributes().get("user_id");
    // ...
}
----

.Kotlin
[source,kotlin,role="secondary"]
----
@GetMapping("/endpoint")
fun foo(authentication: BearerTokenAuthentication): Mono<String?> {
    val userId = authentication.tokenAttributes["user_id"] as String?
    // ...
}
----
====

In that case, you'd want to specify that attribute with the `attributes()` method:

====
.Java
[source,java,role="primary"]
----
client
    .mutateWith(mockOpaqueToken()
        .attributes(attrs -> attrs.put("user_id", "1234"))
    )
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
client
    .mutateWith(mockOpaqueToken()
        .attributes { attrs -> attrs["user_id"] = "1234" }
    )
    .get().uri("/endpoint").exchange()
----
====

[[webflux-testing-opaque-token-principal]]
==== Additional Configurations

There are additional methods, too, for further configuring the authentication; it simply depends on what data your controller expects.

One such is `principal(OAuth2AuthenticatedPrincipal)`, which you can use to configure the complete `OAuth2AuthenticatedPrincipal` instance that underlies the `BearerTokenAuthentication`

It's handy if you:
1. Have your own implementation of `OAuth2AuthenticatedPrincipal`, or
2. Want to specify a different principal name

For example, let's say that your authorization server sends the principal name in the `user_name` attribute instead of the `sub` attribute.
In that case, you can configure an `OAuth2AuthenticatedPrincipal` by hand:

====
.Java
[source,java,role="primary"]
----
Map<String, Object> attributes = Collections.singletonMap("user_name", "foo_user");
OAuth2AuthenticatedPrincipal principal = new DefaultOAuth2AuthenticatedPrincipal(
        (String) attributes.get("user_name"),
        attributes,
        AuthorityUtils.createAuthorityList("SCOPE_message:read"));

client
    .mutateWith(mockOpaqueToken().principal(principal))
    .get().uri("/endpoint").exchange();
----

.Kotlin
[source,kotlin,role="secondary"]
----
val attributes: Map<String, Any> = mapOf(Pair("user_name", "foo_user"))
val principal: OAuth2AuthenticatedPrincipal = DefaultOAuth2AuthenticatedPrincipal(
    attributes["user_name"] as String?,
    attributes,
    AuthorityUtils.createAuthorityList("SCOPE_message:read")
)

client
    .mutateWith(mockOpaqueToken().principal(principal))
    .get().uri("/endpoint").exchange()
----
====

Note that as an alternative to using `mockOpaqueToken()` test support, you can also mock the `OpaqueTokenIntrospector` bean itself with a `@MockBean` annotation.
