Created a test for assigning a string to window.location.

ios/web/navigation/window_location_inttest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "base/mac/bind_objc_block.h"
 #include "base/mac/foundation_util.h"
 #include "base/memory/ptr_util.h"
 #import "base/strings/sys_string_conversions.h"
 #include "base/test/ios/wait_util.h"
 #import "ios/web/public/navigation_item.h"
@@ skipping 21 matching lines @@
 //   and is removed once a button is tapped.  Verifying that the onload text is
 //   visible after tapping a button is equivalent to checking that a load has
 //   occurred as the result of the button tap.
 const char kWindowLocationTestURL[] =
     "http://ios/testing/data/http_server_files/window_location.html";
 
 // Button IDs used in the window.location test page.
 const char kWindowLocationAssignID[] = "location-assign";
 const char kWindowLocationReplaceID[] = "location-replace";
 const char kWindowLocationReloadID[] = "location-reload";
+const char kWindowLocationSetToDOMStringID[] = "set-location-to-dom-string";
 
 // JavaScript functions on the window.location test page.
 NSString* const kUpdateURLScriptFormat = @"updateUrlToLoadText('%s')";
 NSString* const kGetURLScript = @"getUrl()";
 NSString* const kOnLoadCheckScript = @"isOnLoadTextVisible()";
 
 // URL of a sample file-based page.
 const char kSampleFileBasedURL[] =
     "http://ios/testing/data/http_server_files/chromium_logo_page.html";
 
@@ skipping 142 matching lines @@
   ExecuteBlockAndWaitForLoad(window_location_url(), ^{
     ASSERT_TRUE(web::test::TapWebViewElementWithId(web_state(),
                                                    kWindowLocationReloadID));
   });
 
   // Verify that |kOnLoadText| is displayed and that no additional
   // NavigationItems are added.
   EXPECT_TRUE(IsOnLoadTextVisible());
   EXPECT_EQ(1, navigation_manager()->GetItemCount());
 }
+
+// Tests that calling window.location.assign() creates a new NavigationItem.
+TEST_F(WindowLocationTest, WindowLocationSetToDOMString) {
+  // Navigate to about:blank so there is a forward entry to prune.
+  GURL about_blank("about:blank");
+  LoadUrl(about_blank);
+  web::NavigationItem* about_blank_item =
+      navigation_manager()->GetLastCommittedItem();
+
+  // Navigate back to the window.location test page.
+  ExecuteBlockAndWaitForLoad(window_location_url(), ^{
+    navigation_manager()->GoBack();
+  });
+
+  // Set the window.location test URL and tap the window.location.assign()
+  // button.
+  GURL sample_url = web::test::HttpServer::MakeUrl(kSampleFileBasedURL);
+  SetWindowLocationUrl(sample_url);
+  ExecuteBlockAndWaitForLoad(sample_url, ^{
+    ASSERT_TRUE(web::test::TapWebViewElementWithId(
+        web_state(), kWindowLocationSetToDOMStringID));
+  });
+
+  // Verify that |sample_url| was loaded and that |about_blank_item| was pruned.
+  EXPECT_EQ(sample_url, navigation_manager()->GetLastCommittedItem()->GetURL());
+  EXPECT_EQ(NSNotFound, GetIndexOfNavigationItem(about_blank_item));
+}