MD Search Field: Properly respond to external changes to search value.

chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js

Index: chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js
diff --git a/chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js b/chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js
index 268cfa788e0acfe5edaebd062e22a19dbc86366f..bf7b78ed275971847c35646523f77fec832f9a91 100644
--- a/chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js
+++ b/chrome/test/data/webui/cr_elements/cr_toolbar_search_field_tests.js
@@ -86,6 +86,19 @@ cr.define('cr_toolbar_search_field', function() {
 
         assertTrue(field.showingSearch);
       });
+
+      test('opens when value is changed', function() {
+        // Change search value without explicity opening the field first.
+        // Similar to what happens when pasting or dragging into the input
+        // field.
+        simulateSearch('test');
+
+        assertTrue(field.hasSearchText_);

[dpapad, 2016/06/23 00:44:19]

Accessing private variables from within a test ends up testing internal state
instead of behavior. This is sub-optimal, for example imagine a future change
where the data binding
hidden$="[[!hasSearchText_]]
is removed. The test would not break, but the behavior would be broken.

So a better assertion would be the following.
assertFalse(field.$.clearSearch.hidden);
which would break if behavior is broken. You might need to call
Polymer.dom.flush() before the assertion.

[tsergeant, 2016/06/23 01:00:34]

Good point, done.

+        assertTrue(field.showingSearch);
+
+        MockInteractions.tap(field.$.clearSearch);
+        assertFalse(field.showingSearch);
+      });
     });
   }