Do not use Mockito to mock ReactiveAdapterRegistry

spring-webflux/spring-webflux.gradle

@@ -40,7 +40,6 @@ dependencies {
 	testImplementation("jakarta.validation:jakarta.validation-api")
 	testImplementation("io.reactivex.rxjava3:rxjava")
 	testImplementation("io.projectreactor:reactor-test")
-	testImplementation("io.projectreactor.tools:blockhound") // required by Mockito 5's default MockMaker in order to mock ReactiveAdapterRegistry which "contains" SpringCoreBlockHoundIntegration
 	testImplementation("io.micrometer:micrometer-observation-test")
 	testImplementation("io.undertow:undertow-core")
 	testImplementation("org.apache.tomcat.embed:tomcat-embed-core")

spring-webflux/src/test/java/org/springframework/web/reactive/config/DelegatingWebFluxConfigurationIntegrationTests.java

@@ -80,7 +80,7 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 
 	@Test
 	void requestMappingHandlerAdapterWithPrimaryUsesQualifiedReactiveAdapterRegistry() {
-		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class));
+		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class, new ReactiveAdapterRegistry()));
 		RequestMappingHandlerAdapter mappingHandlerAdapter = this.context.getBean(RequestMappingHandlerAdapter.class);
 		assertThat(mappingHandlerAdapter.getReactiveAdapterRegistry()).isSameAs(this.context.getBean("webFluxAdapterRegistry"));
 		assertThat(this.context.getBeansOfType(ReactiveAdapterRegistry.class)).containsOnlyKeys(
@@ -117,7 +117,7 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 
 	@Test
 	void responseEntityResultHandlerWithPrimaryUsesQualifiedReactiveAdapterRegistry() {
-		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class));
+		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class, new ReactiveAdapterRegistry()));
 		ResponseEntityResultHandler responseEntityResultHandler = this.context.getBean(ResponseEntityResultHandler.class);
 		assertThat(responseEntityResultHandler.getAdapterRegistry()).isSameAs(this.context.getBean("webFluxAdapterRegistry"));
 		assertThat(this.context.getBeansOfType(ReactiveAdapterRegistry.class)).containsOnlyKeys(
@@ -143,7 +143,7 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 
 	@Test
 	void responseBodyResultHandlerWithPrimaryUsesQualifiedReactiveAdapterRegistry() {
-		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class));
+		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class, new ReactiveAdapterRegistry()));
 		ResponseBodyResultHandler responseBodyResultHandler = this.context.getBean(ResponseBodyResultHandler.class);
 		assertThat(responseBodyResultHandler.getAdapterRegistry()).isSameAs(this.context.getBean("webFluxAdapterRegistry"));
 		assertThat(this.context.getBeansOfType(ReactiveAdapterRegistry.class)).containsOnlyKeys(
@@ -169,7 +169,7 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 
 	@Test
 	void viewResolutionResultHandlerWithPrimaryUsesQualifiedReactiveAdapterRegistry() {
-		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class));
+		load(registerPrimaryBean("testReactiveAdapterRegistry", ReactiveAdapterRegistry.class, new ReactiveAdapterRegistry()));
 		ViewResolutionResultHandler viewResolutionResultHandler = this.context.getBean(ViewResolutionResultHandler.class);
 		assertThat(viewResolutionResultHandler.getAdapterRegistry()).isSameAs(this.context.getBean("webFluxAdapterRegistry"));
 		assertThat(this.context.getBeansOfType(ReactiveAdapterRegistry.class)).containsOnlyKeys(
@@ -189,6 +189,10 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 		return context -> context.registerBean(beanName, type, () -> mock(type), definition -> definition.setPrimary(true));
 	}
 
+	private <T> Consumer<AnnotationConfigApplicationContext> registerPrimaryBean(String beanName, Class<T> type, T instance) {
+		return context -> context.registerBean(beanName, type, () -> instance, definition -> definition.setPrimary(true));
+	}
+
 	private void load(Consumer<AnnotationConfigApplicationContext> context) {
 		AnnotationConfigApplicationContext testContext = new AnnotationConfigApplicationContext();
 		context.accept(testContext);
@@ -196,4 +200,5 @@ public class DelegatingWebFluxConfigurationIntegrationTests {
 		testContext.refresh();
 		this.context = testContext;
 	}
+
 }