WebTestClient supports customer argument resolvers

Issue: SPR-15495

spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultControllerSpec.java

@@ -35,6 +35,7 @@ import org.springframework.web.reactive.config.DelegatingWebFluxConfiguration;
 import org.springframework.web.reactive.config.PathMatchConfigurer;
 import org.springframework.web.reactive.config.ViewResolverRegistry;
 import org.springframework.web.reactive.config.WebFluxConfigurer;
+import org.springframework.web.reactive.result.method.annotation.ArgumentResolverConfigurer;
 import org.springframework.web.server.adapter.WebHttpHandlerBuilder;
 
 /**
@@ -77,6 +78,12 @@ class DefaultControllerSpec extends AbstractMockServerSpec<WebTestClient.Control
 		return this;
 	}
 
+	@Override
+	public DefaultControllerSpec argumentResolvers(Consumer<ArgumentResolverConfigurer> consumer) {
+		this.configurer.argumentResolverConsumer = consumer;
+		return this;
+	}
+
 	@Override
 	public DefaultControllerSpec pathMatching(Consumer<PathMatchConfigurer> consumer) {
 		this.configurer.pathMatchConsumer = consumer;
@@ -136,6 +143,8 @@ class DefaultControllerSpec extends AbstractMockServerSpec<WebTestClient.Control
 
 		private Consumer<CorsRegistry> corsRegistryConsumer;
 
+		private Consumer<ArgumentResolverConfigurer> argumentResolverConsumer;
+
 		private Consumer<PathMatchConfigurer> pathMatchConsumer;
 
 		private Consumer<ServerCodecConfigurer> messageCodecsConsumer;
@@ -168,6 +177,13 @@ class DefaultControllerSpec extends AbstractMockServerSpec<WebTestClient.Control
 			}
 		}
 
+		@Override
+		public void configureArgumentResolvers(ArgumentResolverConfigurer configurer) {
+			if (this.argumentResolverConsumer != null) {
+				this.argumentResolverConsumer.accept(configurer);
+			}
+		}
+
 		@Override
 		public void configureHttpMessageCodecs(ServerCodecConfigurer configurer) {
 			if (this.messageCodecsConsumer != null) {

spring-test/src/main/java/org/springframework/test/web/reactive/server/WebTestClient.java

@@ -48,6 +48,7 @@ import org.springframework.web.reactive.function.client.ExchangeFunction;
 import org.springframework.web.reactive.function.client.ExchangeStrategies;
 import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.reactive.function.server.RouterFunction;
+import org.springframework.web.reactive.result.method.annotation.ArgumentResolverConfigurer;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.util.UriBuilder;
@@ -243,7 +244,13 @@ public interface WebTestClient {
 		ControllerSpec pathMatching(Consumer<PathMatchConfigurer> consumer);
 
 		/**
-		 * Modify or extend the list of built-in message readers and writers.
+		 * Configure resolvers for custom controller method arguments.
+		 * @see WebFluxConfigurer#configureHttpMessageCodecs
+		 */
+		ControllerSpec argumentResolvers(Consumer<ArgumentResolverConfigurer> configurer);
+
+		/**
+		 * Configure custom HTTP message readers and writers or override built-in ones.
 		 * @see WebFluxConfigurer#configureHttpMessageCodecs
 		 */
 		ControllerSpec httpMessageCodecs(Consumer<ServerCodecConfigurer> configurer);

spring-test/src/test/java/org/springframework/test/web/reactive/server/DefaultControllerSpecTests.java

@@ -16,13 +16,24 @@
 
 package org.springframework.test.web.reactive.server;
 
+import java.util.function.Consumer;
+
 import org.junit.Test;
 
+import org.springframework.format.FormatterRegistry;
 import org.springframework.http.ResponseEntity;
+import org.springframework.http.codec.ServerCodecConfigurer;
 import org.springframework.web.bind.annotation.ControllerAdvice;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
+import org.springframework.web.reactive.config.CorsRegistry;
+import org.springframework.web.reactive.config.PathMatchConfigurer;
+import org.springframework.web.reactive.config.ViewResolverRegistry;
+import org.springframework.web.reactive.result.method.annotation.ArgumentResolverConfigurer;
+
+import static org.junit.Assert.assertNotNull;
 
 /**
  * Unit tests for {@link DefaultControllerSpec}.
@@ -52,6 +63,36 @@ public class DefaultControllerSpecTests {
 				.expectBody(String.class).isEqualTo("Handled exception");
 	}
 
+	@Test
+	public void configurerConsumers() throws Exception {
+
+		TestConsumer<ArgumentResolverConfigurer> argumentResolverConsumer = new TestConsumer<>();
+		TestConsumer<RequestedContentTypeResolverBuilder> contenTypeResolverConsumer = new TestConsumer<>();
+		TestConsumer<CorsRegistry> corsRegistryConsumer = new TestConsumer<>();
+		TestConsumer<FormatterRegistry> formatterConsumer = new TestConsumer<>();
+		TestConsumer<ServerCodecConfigurer> codecsConsumer = new TestConsumer<>();
+		TestConsumer<PathMatchConfigurer> pathMatchingConsumer = new TestConsumer<>();
+		TestConsumer<ViewResolverRegistry> viewResolverConsumer = new TestConsumer<>();
+
+		new DefaultControllerSpec(new MyController())
+				.argumentResolvers(argumentResolverConsumer)
+				.contentTypeResolver(contenTypeResolverConsumer)
+				.corsMappings(corsRegistryConsumer)
+				.formatters(formatterConsumer)
+				.httpMessageCodecs(codecsConsumer)
+				.pathMatching(pathMatchingConsumer)
+				.viewResolvers(viewResolverConsumer)
+				.build();
+
+		assertNotNull(argumentResolverConsumer.getValue());
+		assertNotNull(contenTypeResolverConsumer.getValue());
+		assertNotNull(corsRegistryConsumer.getValue());
+		assertNotNull(formatterConsumer.getValue());
+		assertNotNull(codecsConsumer.getValue());
+		assertNotNull(pathMatchingConsumer.getValue());
+		assertNotNull(viewResolverConsumer.getValue());
+
+	}
 
 	@RestController
 	private static class MyController {
@@ -77,4 +118,19 @@ public class DefaultControllerSpecTests {
 		}
 	}
 
+	private static class TestConsumer<T> implements Consumer<T> {
+
+		private T value;
+
+
+		public T getValue() {
+			return this.value;
+		}
+
+		@Override
+		public void accept(T t) {
+			this.value = t;
+		}
+	}
+
 }