MD Settings: in spell-check page, disable add button when input is empty.

chrome/test/data/webui/settings/languages_page_browsertest.js

 // 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.
 
 /** @fileoverview Suite of tests for settings-languages-page. */
 
 /** @const {string} Path to root from chrome/test/data/webui/settings/. */
 var ROOT_PATH = '../../../../../';
 
 // Polymer BrowserTest fixture.
@@ skipping 429 matching lines @@
         assertFalse(triggerRow.classList.contains('two-line'));
         assertEquals(
             0, triggerRow.querySelector('.secondary').textContent.length);
 
         languagesPage.set(
             'languages.enabled.0.language.supportsSpellcheck', true);
         languagesPage.set('languages.enabled.0.spellCheckEnabled', true);
         assertTrue(triggerRow.classList.contains('two-line'));
         assertLT(
             0, triggerRow.querySelector('.secondary').textContent.length);
+      }
+    });
 
+    if (!cr.isMac) {
+      test('spellcheck edit dictionary page add word button', function() {
+        assertFalse(!!languagesPage.$$('settings-edit-dictionary-page'));
+        var spellCheckCollapse = languagesPage.$.spellCheckCollapse;
         MockInteractions.tap(
             spellCheckCollapse.querySelector('.list-button:last-of-type'));

[dpapad, 2017/02/06 22:40:59]

Are you sure that this selector works as expected? AFAIK first-of-type,
last-of-type can only used with element tags, not CSS clases, for example

div:last-of-type OK
p: first-of-type OK
.foo:last-of-type NOT OK

[scottchen, 2017/02/06 23:38:31]

The (non-)existence of the subpage is checked before and after the target
element is mock-tapped, so I think it's selecting the collapse button as
intended.
Also, :last-of-type seems to work with class. See:
https://jsfiddle.net/dLwyqwwh/

-        assertTrue(!!languagesPage.$$('settings-edit-dictionary-page'));
-      }
-    });
+        var editDictPage = languagesPage.$$('settings-edit-dictionary-page');
+        assertTrue(!!editDictPage);
+        var addWordButton = editDictPage.root.querySelector('paper-button');
+        editDictPage.$.newWord.value = '';
+        assertTrue(!!addWordButton);
+        assertTrue(addWordButton.disabled);
+        editDictPage.$.newWord.value = 'valid word';
+        assertFalse(addWordButton.disabled);
+      });
+    }
   }.bind(this));
 
   // TODO(michaelpg): Test more aspects of the languages UI.
 
   // Run all registered tests.
   mocha.run();
 });