Make cvox2 output feedback more robust when focusing a text field.

chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js

Index: chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js
diff --git a/chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js b/chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js
index 3f32d0ca400195ba699af41f9c70f0463edc5d2d..8bde1059c2d434892b40053510d0e22c52bfabc3 100644
--- a/chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js
+++ b/chrome/browser/resources/chromeos/chromevox/testing/mock_tts.js
@@ -27,6 +27,13 @@ MockTts.prototype = {
    */
   idleUtterances_: [],
 
+  /**
+   * Whether we should skip non-matching utterances. Initially it's set
+   * to true, but after the first matching utterance it's set to false
+   * so that we can assert that no extra unrelated speech is generated.

[David Tseng, 2015/08/19 17:19:25]

I think this is called a strict mock.

+   */

[David Tseng, 2015/08/19 17:19:25]

nit: @private

+  skipNonMatchingUtterances_: true,

[Peter Lundblad, 2015/08/20 08:30:06]

I support this in principal, but it has the potential to be flaky.  In end
to end tests like this there are some things we don't have control over.  When
running these tests locally, I always get a system alert about 'connected
to eth1' and I don't think we can be sure those happen first.  Perhaps we need
to whitelist a few unrelated utterances to be able to enable more strictness.

+
   /** @override */
   speak: function(textString, queueMode, properties) {
     this.process_(textString, false, properties);
@@ -79,6 +86,7 @@ MockTts.prototype = {
   addExpectation_: function(expectedText, opt_expectation, opt_exact) {
     var expectation = opt_expectation ? opt_expectation : {};
 
+    expectation.text = expectedText;
     expectation.predicate = function(actualText) {
       if (opt_exact)
         return actualText === expectedText;
@@ -110,10 +118,23 @@ MockTts.prototype = {
 
     var allUtterances = this.idleUtterances_.concat([utterance]);
     var targetExpectation = this.expectations_.shift();
-    allUtterances = allUtterances.filter(function(u) {
-      return targetExpectation.predicate(u.text);
-    });
+
+    if (this.skipNonMatchingUtterances_) {
+      allUtterances = allUtterances.filter(function(u) {
+        return targetExpectation.predicate(u.text);
+      });
+    } else if (allUtterances.length > 0 &&
+               !targetExpectation.predicate(allUtterances[0].text)) {
+      throw new Error('Mock TTS expected ' + targetExpectation.text +
+                      ' but got ' + allUtterances[0].text);
+      return;
+    }
+
     if (allUtterances.length > 0) {
+      // We got a match. Don't skip any more non-matching utterances
+      // anymore.

[Peter Lundblad, 2015/08/20 08:30:06]

nit: any more, anymore

+      this.skipNonMatchingUtterances_ = false;
+
       var matchingProperties = allUtterances[0].properties;
       this.idleUtterances_.length = 0;
       if (targetExpectation.endCallback)