WebTestClient support for API versioning

Closes gh-34568

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

@@ -56,6 +56,7 @@ import org.springframework.util.CollectionUtils;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MimeType;
 import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.ApiVersionInserter;
 import org.springframework.web.reactive.function.BodyInserter;
 import org.springframework.web.reactive.function.BodyInserters;
 import org.springframework.web.reactive.function.client.ClientRequest;
@@ -88,6 +89,8 @@ class DefaultWebTestClient implements WebTestClient {
 
 	private final @Nullable MultiValueMap<String, String> defaultCookies;
 
+	private final @Nullable ApiVersionInserter apiVersionInserter;
+
 	private final Consumer<EntityExchangeResult<?>> entityResultConsumer;
 
 	private final Duration responseTimeout;
@@ -97,10 +100,11 @@ class DefaultWebTestClient implements WebTestClient {
 	private final AtomicLong requestIndex = new AtomicLong();
 
 
-	DefaultWebTestClient(ClientHttpConnector connector, ExchangeStrategies exchangeStrategies,
+	DefaultWebTestClient(
+			ClientHttpConnector connector, ExchangeStrategies exchangeStrategies,
 			Function<ClientHttpConnector, ExchangeFunction> exchangeFactory, UriBuilderFactory uriBuilderFactory,
 			@Nullable HttpHeaders headers, @Nullable MultiValueMap<String, String> cookies,
-			Consumer<EntityExchangeResult<?>> entityResultConsumer,
+			@Nullable ApiVersionInserter apiVersionInserter, Consumer<EntityExchangeResult<?>> entityResultConsumer,
 			@Nullable Duration responseTimeout, DefaultWebTestClientBuilder clientBuilder) {
 
 		this.wiretapConnector = new WiretapConnector(connector);
@@ -110,6 +114,7 @@ class DefaultWebTestClient implements WebTestClient {
 		this.uriBuilderFactory = uriBuilderFactory;
 		this.defaultHeaders = headers;
 		this.defaultCookies = cookies;
+		this.apiVersionInserter = apiVersionInserter;
 		this.entityResultConsumer = entityResultConsumer;
 		this.responseTimeout = (responseTimeout != null ? responseTimeout : Duration.ofSeconds(5));
 		this.builder = clientBuilder;
@@ -186,6 +191,8 @@ class DefaultWebTestClient implements WebTestClient {
 
 		private @Nullable MultiValueMap<String, String> cookies;
 
+		private @Nullable Object apiVersion;
+
 		private @Nullable BodyInserter<?, ? super ClientHttpRequest> inserter;
 
 		private final Map<String, Object> attributes = new LinkedHashMap<>(4);
@@ -310,6 +317,12 @@ class DefaultWebTestClient implements WebTestClient {
 			return this;
 		}
 
+		@Override
+		public RequestBodySpec apiVersion(Object version) {
+			this.apiVersion = version;
+			return this;
+		}
+
 		@Override
 		public RequestHeadersSpec<?> bodyValue(Object body) {
 			this.inserter = BodyInserters.fromValue(body);
@@ -373,6 +386,10 @@ class DefaultWebTestClient implements WebTestClient {
 						if (!this.headers.isEmpty()) {
 							headersToUse.putAll(this.headers);
 						}
+						if (this.apiVersion != null) {
+							Assert.state(apiVersionInserter != null, "No ApiVersionInserter configured");
+							apiVersionInserter.insertVersion(this.apiVersion, headersToUse);
+						}
 					})
 					.cookies(cookiesToUse -> {
 						if (!CollectionUtils.isEmpty(DefaultWebTestClient.this.defaultCookies)) {
@@ -386,7 +403,12 @@ class DefaultWebTestClient implements WebTestClient {
 		}
 
 		private URI initUri() {
-			return (this.uri != null ? this.uri : DefaultWebTestClient.this.uriBuilderFactory.expand(""));
+			URI uriToUse = this.uri != null ? this.uri : DefaultWebTestClient.this.uriBuilderFactory.expand("");
+			if (this.apiVersion != null) {
+				Assert.state(apiVersionInserter != null, "No ApiVersionInserter configured");
+				uriToUse = apiVersionInserter.insertVersion(this.apiVersion, uriToUse);
+			}
+			return uriToUse;
 		}
 
 	}

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

@@ -37,6 +37,7 @@ import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
+import org.springframework.web.client.ApiVersionInserter;
 import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
 import org.springframework.web.reactive.function.client.ExchangeFunction;
 import org.springframework.web.reactive.function.client.ExchangeFunctions;
@@ -85,6 +86,8 @@ class DefaultWebTestClientBuilder implements WebTestClient.Builder {
 
 	private @Nullable MultiValueMap<String, String> defaultCookies;
 
+	private @Nullable ApiVersionInserter apiVersionInserter;
+
 	private @Nullable List<ExchangeFilterFunction> filters;
 
 	private Consumer<EntityExchangeResult<?>> entityResultConsumer = result -> {};
@@ -142,6 +145,7 @@ class DefaultWebTestClientBuilder implements WebTestClient.Builder {
 		}
 		this.defaultCookies = (other.defaultCookies != null ?
 				new LinkedMultiValueMap<>(other.defaultCookies) : null);
+		this.apiVersionInserter = other.apiVersionInserter;
 		this.filters = (other.filters != null ? new ArrayList<>(other.filters) : null);
 		this.entityResultConsumer = other.entityResultConsumer;
 		this.strategies = other.strategies;
@@ -200,6 +204,12 @@ class DefaultWebTestClientBuilder implements WebTestClient.Builder {
 		return this.defaultCookies;
 	}
 
+	@Override
+	public WebTestClient.Builder apiVersionInserter(ApiVersionInserter apiVersionInserter) {
+		this.apiVersionInserter = apiVersionInserter;
+		return this;
+	}
+
 	@Override
 	public WebTestClient.Builder filter(ExchangeFilterFunction filter) {
 		Assert.notNull(filter, "ExchangeFilterFunction is required");
@@ -283,10 +293,12 @@ class DefaultWebTestClientBuilder implements WebTestClient.Builder {
 					.orElse(exchange);
 
 		};
-		return new DefaultWebTestClient(connectorToUse, exchangeStrategies, exchangeFactory, initUriBuilderFactory(),
-				this.defaultHeaders != null ? HttpHeaders.readOnlyHttpHeaders(this.defaultHeaders) : null,
-				this.defaultCookies != null ? CollectionUtils.unmodifiableMultiValueMap(this.defaultCookies) : null,
-				this.entityResultConsumer, this.responseTimeout, new DefaultWebTestClientBuilder(this));
+		return new DefaultWebTestClient(
+				connectorToUse, exchangeStrategies, exchangeFactory, initUriBuilderFactory(),
+				(this.defaultHeaders != null ? HttpHeaders.readOnlyHttpHeaders(this.defaultHeaders) : null),
+				(this.defaultCookies != null ? CollectionUtils.unmodifiableMultiValueMap(this.defaultCookies) : null),
+				this.apiVersionInserter, this.entityResultConsumer,
+				this.responseTimeout, new DefaultWebTestClientBuilder(this));
 	}
 
 	private static ClientHttpConnector initConnector() {

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

@@ -45,6 +45,8 @@ import org.springframework.test.json.JsonCompareMode;
 import org.springframework.test.json.JsonComparison;
 import org.springframework.util.MultiValueMap;
 import org.springframework.validation.Validator;
+import org.springframework.web.client.ApiVersionFormatter;
+import org.springframework.web.client.ApiVersionInserter;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 import org.springframework.web.reactive.config.BlockingExecutionConfigurer;
 import org.springframework.web.reactive.config.CorsRegistry;
@@ -428,6 +430,15 @@ public interface WebTestClient {
 		 */
 		Builder defaultCookies(Consumer<MultiValueMap<String, String>> cookiesConsumer);
 
+		/**
+		 * Configure an {@link ApiVersionInserter} to abstract how an API version
+		 * specified via {@link RequestHeadersSpec#apiVersion(Object)}
+		 * is inserted into the request.
+		 * @param apiVersionInserter the inserter to use
+		 * @since 7.0
+		 */
+		Builder apiVersionInserter(ApiVersionInserter apiVersionInserter);
+
 		/**
 		 * Add the given filter to the filter chain.
 		 * @param filter the filter to be added to the chain
@@ -643,6 +654,17 @@ public interface WebTestClient {
 		 */
 		S headers(Consumer<HttpHeaders> headersConsumer);
 
+		/**
+		 * Set an API version for the request. The version is inserted into the
+		 * request by the {@link Builder#apiVersionInserter(ApiVersionInserter)
+		 * configured} {@code ApiVersionInserter}.
+		 * @param version the API version of the request; this can be a String or
+		 * some Object that can be formatted the inserter, e.g. through an
+		 * {@link ApiVersionFormatter}.
+		 * @since 7.0
+		 */
+		S apiVersion(Object version);
+
 		/**
 		 * Set the attribute with the given name to the given value.
 		 * @param name the name of the attribute to add

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

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2002-2025 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.test.web.reactive.server.samples;
+
+import java.net.URI;
+import java.util.Map;
+import java.util.function.Consumer;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.client.DefaultApiVersionInserter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * {@link WebTestClient} tests for sending API versions.
+ *
+ * @author Rossen Stoyanchev
+ */
+public class ApiVersionTests {
+
+	private static final String HEADER_NAME = "X-API-Version";
+
+
+	@Test
+	void header() {
+		Map<String, String> result = performRequest(builder -> builder.fromHeader("X-API-Version"));
+		assertThat(result.get(HEADER_NAME)).isEqualTo("1.2");
+	}
+
+	@Test
+	void queryParam() {
+		Map<String, String> result = performRequest(builder -> builder.fromQueryParam("api-version"));
+		assertThat(result.get("query")).isEqualTo("api-version=1.2");
+	}
+
+	@Test
+	void pathSegment() {
+		Map<String, String> result = performRequest(builder -> builder.fromPathSegment(0));
+		assertThat(result.get("path")).isEqualTo("/1.2/path");
+	}
+
+	@SuppressWarnings("unchecked")
+	private Map<String, String> performRequest(Consumer<DefaultApiVersionInserter.Builder> consumer) {
+		DefaultApiVersionInserter.Builder builder = DefaultApiVersionInserter.builder();
+		consumer.accept(builder);
+		return (Map<String, String>) WebTestClient.bindToController(new TestController())
+				.configureClient()
+				.baseUrl("/path")
+				.apiVersionInserter(builder.build())
+				.build()
+				.get()
+				.apiVersion(1.2)
+				.exchange()
+				.returnResult(Map.class)
+				.getResponseBody()
+				.blockFirst();
+	}
+
+
+	@RestController
+	static class TestController {
+
+		@GetMapping("/**")
+		Map<String, String> handle(ServerHttpRequest request) {
+			URI uri = request.getURI();
+			String query = uri.getQuery();
+			String header = request.getHeaders().getFirst(HEADER_NAME);
+			return Map.of("path", uri.getRawPath(),
+					"query", (query != null ? query : ""),
+					HEADER_NAME, (header != null ? header : ""));
+		}
+	}
+
+}