Support API versioning via MediaType parameter

Closes gh-35050

spring-web/src/test/java/org/springframework/web/accept/MediaTypeParamApiVersionResolverTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2002-present 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.web.accept;
+
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.testfixture.servlet.MockHttpServletRequest;
+import org.springframework.web.util.ServletRequestPathUtils;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Unit tests for {@link MediaTypeParamApiVersionResolver}.
+ * @author Rossen Stoyanchev
+ */
+public class MediaTypeParamApiVersionResolverTests {
+
+	private final MediaType mediaType = MediaType.parseMediaType("application/x.abc+json");
+
+	private final ApiVersionResolver resolver = new MediaTypeParamApiVersionResolver(mediaType, "version");
+
+	private final MockHttpServletRequest request = new MockHttpServletRequest("GET", "/path");
+
+
+	@Test
+	void resolveFromAccept() {
+		String version = "3";
+		this.request.addHeader("Accept", getMediaType(version));
+		testResolve(this.resolver, this.request, version);
+	}
+
+	@Test
+	void resolveFromContentType() {
+		String version = "3";
+		this.request.setContentType(getMediaType(version).toString());
+		testResolve(this.resolver, this.request, version);
+	}
+
+	@Test
+	void wildcard() {
+		MediaType compatibleMediaType = MediaType.parseMediaType("application/*+json");
+		ApiVersionResolver resolver = new MediaTypeParamApiVersionResolver(compatibleMediaType, "version");
+
+		String version = "3";
+		this.request.addHeader("Accept", getMediaType(version));
+		testResolve(resolver, this.request, version);
+	}
+
+	private MediaType getMediaType(String version) {
+		return new MediaType(this.mediaType, Map.of("version", version));
+	}
+
+	private void testResolve(ApiVersionResolver resolver, MockHttpServletRequest request, String expected) {
+		try {
+			ServletRequestPathUtils.parseAndCache(request);
+			String actual = resolver.resolveVersion(request);
+			assertThat(actual).isEqualTo(expected);
+		}
+		finally {
+			ServletRequestPathUtils.clearParsedRequestPath(request);
+		}
+	}
+
+}