Add params(MultiValueMap) to MockMvc

Issue: SPR-13801

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

@@ -151,6 +151,21 @@ public class MockHttpServletRequestBuilder
 		return this;
 	}
 
+	/**
+	 * Add request parameters to the {@link MockHttpServletRequest} for example
+	 * such as when testing a form submission. If called more than once, the new
+	 * values are added.
+	 * @param params the parameters to add
+	 */
+	public MockHttpServletRequestBuilder params(MultiValueMap<String, String> params) {
+		for (String name : params.keySet()) {
+			for (String value : params.get(name)) {
+				this.parameters.add(name, value);
+			}
+		}
+		return this;
+	}
+
 	/**
 	 * Add a header to the request. Values are always added.
 	 * @param name the header name