MockMvc request builder preserves double slashes

The MockHttpServletRequestBuilder now uses java.net.URI internally
rather than UriComponents.

This means that for the MockMvcRequestBuilders method variants that
accept a java.net.URI we can use it as is. The difference is almost
none but it does mean that you can create a URI with double slashes
(for testing purposes) and have it remain that way.

Issue: SPR-13435

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

@@ -16,6 +16,8 @@
 package org.springframework.test.web.servlet.request;
 
 import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.security.Principal;
 import java.util.Arrays;
 import java.util.Collections;
@@ -91,6 +93,16 @@ public class MockHttpServletRequestBuilderTests {
 		assertEquals("/foo%20bar", request.getRequestURI());
 	}
 
+	// SPR-13435
+
+	@Test
+	public void requestUriWithDoubleSlashes() throws URISyntaxException {
+		this.builder = new MockHttpServletRequestBuilder(HttpMethod.GET, new URI("/test//currentlyValid/0"));
+		MockHttpServletRequest request = this.builder.buildRequest(this.servletContext);
+
+		assertEquals("/test//currentlyValid/0", request.getRequestURI());
+	}
+
 	@Test
 	public void contextPathEmpty() {
 		this.builder = new MockHttpServletRequestBuilder(HttpMethod.GET, "/foo");