Handle URI as candidate for a merge from a parent builder

Closes gh-33057

spring-test/src/main/java/org/springframework/test/web/servlet/request/AbstractMockHttpServletRequestBuilder.java

@@ -592,6 +592,9 @@ public Object merge(@Nullable Object parent) {
 		if (!(parent instanceof AbstractMockHttpServletRequestBuilder<?> parentBuilder)) {
 			throw new IllegalArgumentException("Cannot merge with [" + parent.getClass().getName() + "]");
 		}
+		if (this.uri == null) {
+			this.uri = parentBuilder.uri;
+		}
 		if (!StringUtils.hasText(this.contextPath)) {
 			this.contextPath = parentBuilder.contextPath;
 		}

spring-test/src/test/java/org/springframework/test/web/servlet/request/AbstractMockHttpServletRequestBuilderTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2002-2024 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.servlet.request;
+
+import jakarta.servlet.ServletContext;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.http.HttpMethod;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockServletContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link AbstractMockHttpServletRequestBuilder}
+ *
+ * @author Stephane Nicoll
+ */
+class AbstractMockHttpServletRequestBuilderTests {
+
+	private final ServletContext servletContext = new MockServletContext();
+
+
+	@Test
+	void mergeUriWhenUriIsNotSet() {
+		TestRequestBuilder parentBuilder = new TestRequestBuilder(HttpMethod.GET).uri("/test");
+		TestRequestBuilder builder = new TestRequestBuilder(HttpMethod.POST);
+		builder.merge(parentBuilder);
+
+		MockHttpServletRequest request = buildRequest(builder);
+		assertThat(request.getRequestURI()).isEqualTo("/test");
+		assertThat(request.getMethod()).isEqualTo(HttpMethod.POST.name());
+	}
+
+	@Test
+	void mergeUriWhenUriIsSetDoesNotOverride() {
+		TestRequestBuilder parentBuilder = new TestRequestBuilder(HttpMethod.GET).uri("/test");
+		TestRequestBuilder builder = new TestRequestBuilder(HttpMethod.POST).uri("/another");
+		builder.merge(parentBuilder);
+
+		MockHttpServletRequest request = buildRequest(builder);
+		assertThat(request.getRequestURI()).isEqualTo("/another");
+		assertThat(request.getMethod()).isEqualTo(HttpMethod.POST.name());
+	}
+
+
+	private MockHttpServletRequest buildRequest(AbstractMockHttpServletRequestBuilder<?> builder) {
+		return builder.buildRequest(this.servletContext);
+	}
+
+
+	private static class TestRequestBuilder extends AbstractMockHttpServletRequestBuilder<TestRequestBuilder> {
+
+		TestRequestBuilder(HttpMethod httpMethod) {
+			super(httpMethod);
+		}
+	}
+
+}