Improve checks on URI string in MockMvc request builder

Closes gh-24556

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -49,6 +49,7 @@ import org.springframework.web.servlet.support.SessionFlashMapManager;
 import org.springframework.web.util.UriComponentsBuilder;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 
 /**
  * Unit tests for building a {@link MockHttpServletRequest} with
@@ -88,7 +89,8 @@ public class MockHttpServletRequestBuilderTests {
 		assertThat(request.getServerName()).isEqualTo("java.sun.com");
 		assertThat(request.getServerPort()).isEqualTo(8080);
 		assertThat(request.getRequestURI()).isEqualTo("/javase/6/docs/api/java/util/BitSet.html");
-		assertThat(request.getRequestURL().toString()).isEqualTo("https://java.sun.com:8080/javase/6/docs/api/java/util/BitSet.html");
+		assertThat(request.getRequestURL().toString())
+				.isEqualTo("https://java.sun.com:8080/javase/6/docs/api/java/util/BitSet.html");
 	}
 
 	@Test
@@ -107,6 +109,12 @@ public class MockHttpServletRequestBuilderTests {
 		assertThat(request.getRequestURI()).isEqualTo("/test//currentlyValid/0");
 	}
 
+	@Test // gh-24556
+	public void requestUriWithoutScheme() {
+		assertThatIllegalArgumentException().isThrownBy(() -> MockMvcRequestBuilders.get("localhost:8080/path"))
+				.withMessage("'url' should start with a path or be a complete HTTP URL: localhost:8080/path");
+	}
+
 	@Test
 	public void contextPathEmpty() {
 		this.builder = new MockHttpServletRequestBuilder(HttpMethod.GET, "/foo");