Return Builder from sslInfo() builder method for MockServerHttpRequest

Prior to this commit, the sslInfo() method in MockServerHttpRequest's
BaseBuilder returned void, which prevented it from being used with the
intended fluent Builder pattern.

This commit changes the return type to the builder (B) for proper method
chaining.

Closes gh-35075

Author: sbrannen

spring-test/src/main/java/org/springframework/mock/http/server/reactive/MockServerHttpRequest.java

@@ -258,7 +258,7 @@ public interface BaseBuilder<B extends BaseBuilder<B>> {
 		/**
 		 * Set SSL session information and certificates.
 		 */
-		void sslInfo(SslInfo sslInfo);
+		B sslInfo(SslInfo sslInfo);
 
 		/**
 		 * Add one or more cookies.
@@ -443,8 +443,9 @@ public BodyBuilder localAddress(InetSocketAddress localAddress) {
 		}
 
 		@Override
-		public void sslInfo(SslInfo sslInfo) {
+		public BodyBuilder sslInfo(SslInfo sslInfo) {
 			this.sslInfo = sslInfo;
+			return this;
 		}
 
 		@Override

spring-test/src/test/java/org/springframework/mock/http/server/reactive/MockServerHttpRequestTests.java

@@ -25,6 +25,7 @@
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.mockito.internal.util.MockUtil;
 
 import org.springframework.http.HttpCookie;
 import org.springframework.http.HttpHeaders;
@@ -33,6 +34,7 @@
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.junit.jupiter.api.Named.named;
+import static org.mockito.Mockito.mock;
 
 /**
  * Tests for {@link MockServerHttpRequest}.
@@ -66,6 +68,19 @@ void queryParams() {
 		assertThat(request.getURI().toString()).isEqualTo("/foo%20bar?a=b&name%20A=value%20A1&name%20A=value%20A2&name%20B=value%20B1");
 	}
 
+	/**
+	 * Ensure that {@code sslInfo()} can be used with the fluent builder pattern.
+	 */
+	@Test  // gh-35075
+	void sslInfo() {
+		MockServerHttpRequest request = MockServerHttpRequest.get("/test")
+				.sslInfo(mock())
+				.build();
+
+		assertThat(request.getSslInfo()).as("is mock").satisfies(sslInfo -> MockUtil.isMock(sslInfo));
+		assertThat(request.getURI().toString()).isEqualTo("/test");
+	}
+
 	@ParameterizedTest(name = "[{index}] {0}")
 	@MethodSource
 	void httpMethodNotNullOrEmpty(ThrowingCallable callable) {

spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/MockServerHttpRequest.java

@@ -258,7 +258,7 @@ public interface BaseBuilder<B extends BaseBuilder<B>> {
 		/**
 		 * Set SSL session information and certificates.
 		 */
-		void sslInfo(SslInfo sslInfo);
+		B sslInfo(SslInfo sslInfo);
 
 		/**
 		 * Add one or more cookies.
@@ -458,8 +458,9 @@ public BodyBuilder localAddress(InetSocketAddress localAddress) {
 		}
 
 		@Override
-		public void sslInfo(SslInfo sslInfo) {
+		public BodyBuilder sslInfo(SslInfo sslInfo) {
 			this.sslInfo = sslInfo;
+			return this;
 		}
 
 		@Override