ChromeVox: Language switching test infrastructure clean up.

This does two things:
1. Cleans up the language switching code to use consistent terms. Most
notably, it changes all instances of "inner-node switching" to
"sub-node switching".
2. Cleans up the language switching test infrastructure. A test
naming scheme was implemented to easily communicate the purpose of
each test. Also, tests were added to cover the two language switching
behaviors: node-level and sub-node-level switching. Each document
in the test databank is tested using node-level and sub-node-level
switching.

Bug: 923068
Change-Id: Ia16b785381966d97e089aae5dc08e23173876d08
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1754703
Commit-Queue: Akihiro Ota <akihiroota@chromium.org>
Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Reviewed-by: Chris Hall <chrishall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690998}

chrome/browser/resources/chromeos/chromevox/cvox2/background/language_switching.js

@@ -5,29 +5,30 @@
 /**
  * @fileoverview Provides language switching services for ChromeVox, which
  * uses language detection information to automatically change the ChromeVox
- * output language.
+ * output voice.
  */
 
 goog.provide('LanguageSwitching');
 
 /**
  * The current output language. Initialize to the language of the browser or
- * empty string if unavailable.
+ * empty string if the former is unavailable.
  * @private {string}
  */
 LanguageSwitching.currentLanguage_ =
     chrome.i18n.getUILanguage().toLowerCase() || '';
 
 /**
- * Confidence threshold to meet before assigning inner-node language.
+ * Confidence threshold to meet before assigning sub-node language.
  * @const
  * @private {number}
  */
-LanguageSwitching.PROBABILITY_THRESHOLD = 0.9;
+LanguageSwitching.PROBABILITY_THRESHOLD_ = 0.9;
 
 /**
- * Stores whether or not ChromeVox inner-node language switching is enabled or
- * disabled.
+ * Stores whether or not ChromeVox sub-node language switching is enabled.
+ * Set to false as default, as sub-node language detection is still
+ * experimental.
  * @private {boolean}
  */
 LanguageSwitching.sub_node_switching_enabled_ = false;
@@ -36,8 +37,7 @@ LanguageSwitching.sub_node_switching_enabled_ = false;
  * Initialization function for language switching.
  */
 LanguageSwitching.init = function() {
-  // Enable inner-node language switching if inner-node switching feature flag
-  // is enabled.
+  // Enable sub-node language switching if feature flag is enabled.
   chrome.commandLinePrivate.hasSwitch(
       'enable-experimental-accessibility-chromevox-sub-node-language-' +
           'switching',
@@ -64,7 +64,6 @@ LanguageSwitching.assignLanguagesForStringAttribute = function(
     return;
   var stringAttributeValue = node[stringAttribute];
   var languageAnnotation;
-
   // Quick note:
   // The decideNewLanguage function, which contains the core language switching
   // logic, is setup to prefer sub-node switching if the detected language's
@@ -74,18 +73,10 @@ LanguageSwitching.assignLanguagesForStringAttribute = function(
     languageAnnotation =
         node.languageAnnotationForStringAttribute(stringAttribute);
   } else {
-    // Use node-level language switching if inner-node switching is
-    // disabled. We use this logic because the API is disabled when sub-node
-    // switching is disabled.
     var nodeLevelLanguageData = {};
     // Ensure that we span the entire stringAttributeValue.
     nodeLevelLanguageData.startIndex = 0;
     nodeLevelLanguageData.endIndex = stringAttributeValue.length;
-    // To force the decideNewLanguage function to use node-level switching, we
-    // pass in an empty language with probability that doesn't exceed the
-    // PROBABILITY_THRESHOLD. As previously mentioned, if we are not confident
-    // enough in inner-node detected languages, we fall back on node-level
-    // language.
     nodeLevelLanguageData.language = '';
     nodeLevelLanguageData.probability = 0;
     languageAnnotation = [nodeLevelLanguageData];
@@ -100,9 +91,10 @@ LanguageSwitching.assignLanguagesForStringAttribute = function(
         stringAttributeValue || '', LanguageSwitching.currentLanguage_);
     return;
   }
+
   // Split output based on language annotation.
   // Each object in languageAnnotation contains a language, probability,
-  // and start/end indices that define a substring.
+  // and start/end indices that define a substring of stringAttributeValue.
   for (var i = 0; i < languageAnnotation.length; ++i) {
     var speechProps = new Output.SpeechProperties();
     var startIndex = languageAnnotation[i].startIndex;
@@ -130,14 +122,14 @@ LanguageSwitching.assignLanguagesForStringAttribute = function(
 /**
  * Run error checks on language data and decide new output language.
  * @param {!AutomationNode} node
- * @param {string} innerNodeLanguage
+ * @param {string} subNodeLanguage
  * @param {number} probability
  * @return {string}
  */
 LanguageSwitching.decideNewLanguage = function(
-    node, innerNodeLanguage, probability) {
+    node, subNodeLanguage, probability) {
   // Use the following priority rankings when deciding language.
-  // 1. Inner-node language. If we can detect inner-node language with a high
+  // 1. Sub-node language. If we can detect sub-node language with a high
   // enough probability of accuracy, then we should use it.
   // 2. Node-level detected language.
   // 3. Author-provided language. This language is also assigned at the node
@@ -145,9 +137,9 @@ LanguageSwitching.decideNewLanguage = function(
   // 4. LanguageSwitching.currentLanguage_. If we do not have enough language
   // data, then we should not switch languages.
 
-  // Use innerNodeLanguage if probability exceeds threshold.
-  if (probability > LanguageSwitching.PROBABILITY_THRESHOLD)
-    return innerNodeLanguage.toLowerCase();
+  // Use subNodeLanguage if probability exceeds threshold.
+  if (probability > LanguageSwitching.PROBABILITY_THRESHOLD_)
+    return subNodeLanguage.toLowerCase();
 
   // Use detected language as nodeLevelLanguage, if present.
   // If no detected language, use author-provided language.
@@ -181,7 +173,7 @@ LanguageSwitching.decideNewLanguage = function(
 };
 
 /**
- * Returns a unicode-aware substring of text from startIndex to endIndex.
+ * Returns a unicode-aware substring of |text| from startIndex to endIndex.
  * @param {string} text
  * @param {number} startIndex
  * @param {number} endIndex

chrome/browser/resources/chromeos/chromevox/cvox2/background/language_switching_test.extjs

@@ -83,82 +83,96 @@ ChromeVoxLanguageSwitchingTest.prototype = {
     }
   },
 
-  multipleLanguagesDoc: function() {/*!
-    <p lang="es">Hola.</p>
-    <p lang="en">Hello.</p>
-    <p lang="fr">Salut.</p>
-    <span lang="it">Ciao amico.</span>
-  */},
 
-  nestedLanguagesDoc: function() {/*!
-    <p id="breakfast" lang="en">In the morning, I sometimes eat breakfast.</p>
-    <p id="lunch" lang="fr">Dans l'apres-midi, je dejeune.</p>
-    <p id="greeting" lang="en">
-      Hello it's a pleasure to meet you.
-      <span lang="fr">Comment ca va?</span>Switching back to English.
-      <span lang="es">Hola.</span>Goodbye.
+  // Test documents //
+
+
+  // The purpose of this doc is to test functionality with three-letter language
+  // codes. Asturian has a language code of 'ast'. It is a language spoken
+  // in Principality of Asturias, Spain.
+  asturianAndJapaneseDoc: function() {/*!
+    <meta charset="utf-8">
+    <p lang="ja">ど</p>
+    <p lang="ast">
+      Pretend that this text is Asturian. Testing three-letter language code logic.
     </p>
   */},
 
   buttonAndLinkDoc: function() {/*!
     <body lang="es">
-      <p>This is a paragraph, spoken in English.</p>
-      <button type="submit">This is a button, spoken in English.</button>
+      <p>This is a paragraph, written in English.</p>
+      <button type="submit">This is a button, written in English.</button>
       <a href="https://www.google.com">Este es un enlace.</a>
     </body>
   */},
 
-  japaneseAndEnglishDoc: function() {/*!
-    <meta charset="utf-8">
-    <p>Hello, my name is 太田あきひろ. It's a pleasure to meet you. どうぞよろしくお願いします.</p>
-  */},
-
-  switchWhenUnlabeledDoc: function() {/*!
-  <meta charset="utf-8">
-  <p>This text should be read in English. 차에 한하여 중임할 수. Followed by English.</p>
-  */},
-
-  noSwitchEnglishFrenchDoc: function() {/*!
+  englishAndFrenchUnlabeledDoc: function() {/*!
     <p>
       This entire object should be read in English, even the following French passage:
       salut mon ami! Ca va? Bien, et toi? It's hard to differentiate between latin-based languages.
     </p>
   */},
 
+  englishAndKoreanUnlabeledDoc: function() {/*!
+    <meta charset="utf-8">
+    <p>This text is written in English. 차에 한하여 중임할 수. This text is also written in English.</p>
+  */},
+
   japaneseAndChineseUnlabeledDoc: function() {/*!
     <meta charset="utf-8">
-    <p>
+    <p id="text">
       天気はいいですね. 右万諭全中結社原済権人点掲年難出面者会追
     </p>
   */},
 
-  japaneseAndKoreanNotEnoughJapaneseDoc: function() {/*!
+  japaneseAndEnglishUnlabeledDoc: function() {/*!
+    <meta charset="utf-8">
+    <p>Hello, my name is 太田あきひろ. It's a pleasure to meet you. どうぞよろしくお願いします.</p>
+  */},
+
+  japaneseAndKoreanUnlabeledDoc: function() {/*!
     <meta charset="utf-8">
     <p lang="ko">
       私は. 법률이 정하는 바에 의하여 대법관이 아닌 법관을 둘 수 있다
     </p>
   */},
 
-  unlabeledSingleCharacterDoc: function() {/*!
+  japaneseCharacterUnlabeledDoc: function() {/*!
     <meta charset="utf-8">
     <p>ど</p>
   */},
 
-  // The purpose of this doc is to test functionality with three-letter language
-  // codes. Asturian has a language code of 'ast'. It is a language spoken
-  // in Principality of Asturias, Spain.
-  asturianAndJapaneseDoc: function() {/*!
-    <meta charset="utf-8">
-    <p lang="ja">ど</p>
-    <p lang="ast">
-      Pretend that this text is Asturian. Testing three-letter language code logic.
+  multipleLanguagesLabeledDoc: function() {/*!
+    <p lang="es">Hola.</p>
+    <p lang="en">Hello.</p>
+    <p lang="fr">Salut.</p>
+    <span lang="it">Ciao amico.</span>
+  */},
+
+  nestedLanguagesLabeledDoc: function() {/*!
+    <p id="breakfast" lang="en">In the morning, I sometimes eat breakfast.</p>
+    <p id="lunch" lang="fr">Dans l'apres-midi, je dejeune.</p>
+    <p id="greeting" lang="en">
+      Hello it's a pleasure to meet you.
+      <span lang="fr">Comment ca va?</span>Switching back to English.
+      <span lang="es">Hola.</span>Goodbye.
     </p>
   */},
 };
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'MultipleLanguagesTest', function() {
+// Overview:
+// The naming scheme of the language switching tests is as follows:
+// <switching_behavior>_<test_document>_Test.
+// <switching_behavior>: Whether the test is testing node-level or sub-node-level switching.
+// <test_document>: The name of the document the test uses.
+// Example: NodeLevelSwitching_MultipleLanguagesLabeledDoc_Test
+// Each group of tests test the two switching behaviors with various labelings.
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_MultipleLanguagesLabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.multipleLanguagesDoc, function() {
+    this.runWithLoadedTree(this.multipleLanguagesLabeledDoc, function() {
       // Turn on language switching.
       localStorage['languageSwitching'] = 'true';
       mockFeedback.call(doCmd('jumpToTop')).expectSpeechWithLanguage('es', 'español: Hola.');
@@ -169,9 +183,26 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'MultipleLanguagesTest', function() {
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'NestedLanguagesTest', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_MultipleLanguagesLabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.nestedLanguagesDoc, function() {
+    this.runWithLoadedTree(this.multipleLanguagesLabeledDoc, function() {
+      localStorage['languageSwitching'] = 'true';
+      // Disable sub-node-level switching.
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop')).expectSpeechWithLanguage('es', 'español: Hola.');
+      mockFeedback.call(doCmd('nextLine')).expectSpeechWithLanguage('en', 'English: Hello.');
+      mockFeedback.call(doCmd('nextLine')).expectSpeechWithLanguage('fr', 'français: Salut.');
+      mockFeedback.call(doCmd('nextLine')).expectSpeechWithLanguage('it', 'italiano: Ciao amico.');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_NestedLanguagesLabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.nestedLanguagesLabeledDoc, function() {
       localStorage['languageSwitching'] = 'true';
       // We should be able to switch languages when each component is labeled
       // with a language.
@@ -195,20 +226,45 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'NestedLanguagesTest', function() {
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'ButtonAndLinkTest', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_NestedLanguagesLabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.nestedLanguagesLabeledDoc, function() {
+      localStorage['languageSwitching'] = 'true';
+      // Disable sub-node-switching.
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('en', 'In the morning, I sometimes eat breakfast.');
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('fr', "français: Dans l'apres-midi, je dejeune.");
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('en', "English: Hello it's a pleasure to meet you. ");
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('fr', 'français: Comment ca va?');
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('en', 'English: Switching back to English. ');
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('es', 'español: Hola.');
+      mockFeedback.call(doCmd('nextLine'))
+          .expectSpeechWithLanguage('en', 'English: Goodbye.');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_ButtonAndLinkDoc_Test', function() {
   var mockFeedback = this.createMockFeedback();
   this.runWithLoadedTree(this.buttonAndLinkDoc, function(root) {
     localStorage['languageSwitching'] = 'true';
     mockFeedback.call(doCmd('jumpToTop'))
-      // Inner-node language detection is able to label this as 'en' and
+      // Sub-node language detection is able to label this as 'en' and
       // overwrite the author-provided language of 'es'.
       // LanguageSwitching.currentLanguage_ is initialized to 'en'. Do not
       // prepend 'English' because language does not switch.
-      .expectSpeechWithLanguage('en', 'This is a paragraph, spoken in English.')
+      .expectSpeechWithLanguage('en', 'This is a paragraph, written in English.')
       .call(doCmd('nextObject'))
-      // Even though this is unlabeled, CLD3 is able to determine, with high
-      // confidence, that this is English text.
-      .expectSpeechWithLanguage('en', 'This is a button, spoken in English.')
+      // CLD3 is able to determine, with high confidence, that this is English text.
+      .expectSpeechWithLanguage('en', 'This is a button, written in English.')
       .expectSpeechWithLanguage(undefined, 'Button', 'Press Search+Space to activate.')
       .call(doCmd('nextObject'))
       .expectSpeechWithLanguage('es', 'español: Este es un enlace.')
@@ -217,9 +273,31 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'ButtonAndLinkTest', function() {
   });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndEnglishUnlabeledTest', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_ButtonAndLinkDoc_Test', function() {
   var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.japaneseAndEnglishDoc, function(root) {
+  this.runWithLoadedTree(this.buttonAndLinkDoc, function(root) {
+    localStorage['languageSwitching'] = 'true';
+    // Disable sub-node-switching.
+    LanguageSwitching.sub_node_switching_enabled_ = false;
+    mockFeedback.call(doCmd('jumpToTop'))
+      // Sub-node language detection is disabled, so we are not able to detect + switch to English
+      // on any of these nodes. Instead, we use the author-provided language of 'es'.
+      .expectSpeechWithLanguage('es', 'español: This is a paragraph, written in English.')
+      .call(doCmd('nextObject'))
+      .expectSpeechWithLanguage('es', 'This is a button, written in English.')
+      .expectSpeechWithLanguage(undefined, 'Button', 'Press Search+Space to activate.')
+      .call(doCmd('nextObject'))
+      .expectSpeechWithLanguage('es', 'Este es un enlace.')
+      .expectSpeechWithLanguage(undefined, 'Link');
+    mockFeedback.replay();
+  });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest','SubNodeLevelSwitching_JapaneseAndEnglishUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.japaneseAndEnglishUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // We are able to separate out English and Japanese because they use
       // different scripts.
@@ -228,7 +306,7 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndEnglishUnlabeledTest', func
         // prepend 'English' because language does not switch.
         .expectSpeechWithLanguage('en', 'Hello, my name is ')
         .expectSpeechWithLanguage('ja', '日本語: 太田あきひろ. ')
-      // Expect 'en-us' because inner-node language of 'en' doesn't come with
+        // Expect 'en-us' because sub-node language of 'en' doesn't come with
         // high enough probability. We fall back on node-level detected language,
         // which is 'en-us'.
         .expectSpeechWithLanguage('en-us', "English: It's a pleasure to meet you. ")
@@ -237,10 +315,10 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndEnglishUnlabeledTest', func
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndEnglishUnlabeledTestSubNodeSwitchingDisabled',
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_JapaneseAndEnglishUnlabeledDoc_Test',
   function() {
     var mockFeedback = this.createMockFeedback();
-    this.runWithLoadedTree(this.japaneseAndEnglishDoc, function(root) {
+    this.runWithLoadedTree(this.japaneseAndEnglishUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // Disable sub-node-switching.
       LanguageSwitching.sub_node_switching_enabled_ = false;
@@ -255,28 +333,46 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndEnglishUnlabeledTestSubNode
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'SwitchWhenUnlabeledTest', function() {
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_EnglishAndKoreanUnlabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.switchWhenUnlabeledDoc, function(root) {
+    this.runWithLoadedTree(this.englishAndKoreanUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // We are able to separate out English and Korean because they use
       // different scripts.
       mockFeedback.call(doCmd('jumpToTop'))
         // LanguageSwitching.currentLanguage_ is initialized to 'en'. Do not
         // prepend 'English' because language does not switch.
-      .expectSpeechWithLanguage('en', 'This text should be read in English. ')
+        .expectSpeechWithLanguage('en', 'This text is written in English. ')
         .expectSpeechWithLanguage('ko', '한국어: 차에 한하여 중임할 수. ')
-      // Expect 'en-us' because inner-node language of 'en' doesn't come with
+        // Expect 'en-us' because sub-node language of 'en' doesn't come with
         // high enough probability. We fall back on node-level detected language,
         // which is 'en-us'.
-      .expectSpeechWithLanguage('en-us', 'English: Followed by English.');
+        .expectSpeechWithLanguage('en', 'English: This text is also written in English.');
+      mockFeedback.replay();
+    });
+});
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_EnglishAndKoreanUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.englishAndKoreanUnlabeledDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      // Disable sub-node-switching
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+        .expectSpeechWithLanguage('en-us', 'This text is written in English. 차에 한하여 중임할 수.'
+          + ' This text is also written in English.');
       mockFeedback.replay();
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'NoSwitchEnglishFrenchTest', function() {
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_EnglishAndFrenchUnlabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.noSwitchEnglishFrenchDoc, function(root) {
+    this.runWithLoadedTree(this.englishAndFrenchUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // Unable to separate out English and French when unlabeled.
       mockFeedback.call(doCmd('jumpToTop'))
@@ -289,9 +385,25 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'NoSwitchEnglishFrenchTest', function()
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'UnlabeledSingleCharacterTest', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_EnglishAndFrenchUnlabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.unlabeledSingleCharacterDoc, function(root) {
+    this.runWithLoadedTree(this.englishAndFrenchUnlabeledDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+        .expectSpeechWithLanguage('en', 'This entire object should be read in English, even'
+        + ' the following French passage: salut mon ami! Ca va? Bien, et toi? It\'s hard to'
+        + ' differentiate between latin-based languages.');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_JapaneseCharacterUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.japaneseCharacterUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // We are able to detect and switch at the character level if the character
       // is unique to a certian script. In this case, 'ど' only appears in
@@ -302,7 +414,21 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'UnlabeledSingleCharacterTest', functio
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndChineseUnlabeled', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_JapaneseCharacterUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.japaneseCharacterUnlabeledDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('en-us', 'ど');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest','SubNodeLevelSwitching_JapaneseAndChineseUnlabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
     this.runWithLoadedTree(this.japaneseAndChineseUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
@@ -314,9 +440,44 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndChineseUnlabeled', function
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndKoreanNotEnoughJapanese', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_JapaneseAndChineseUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.japaneseAndChineseUnlabeledDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('en-us', '天気はいいですね. 右万諭全中結社原済権人点掲年難出面者会追');
+      mockFeedback.replay();
+    });
+});
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_JapaneseAndChineseLabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    // Only difference between doc used in this test and this.japaneseAndChineseUnlabeledDoc is the
+    // lang="zh" attribute.
+    this.runWithLoadedTree(
+      function() {/*!
+        <meta charset="utf-8">
+        <p lang="zh">
+          天気はいいですね. 右万諭全中結社原済権人点掲年難出面者会追
+        </p>
+    */},
+    function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('zh', '中文: 天気はいいですね. 右万諭全中結社原済権人点掲年難出面者会追');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_JapaneseAndKoreanUnlabeledDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.japaneseAndKoreanNotEnoughJapaneseDoc, function(root) {
+    this.runWithLoadedTree(this.japaneseAndKoreanUnlabeledDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
       // Unable to separate out Japanese and Korean if unlabeled.
       mockFeedback.call(doCmd('jumpToTop'))
@@ -326,7 +487,23 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'JapaneseAndKoreanNotEnoughJapanese', f
     });
 });
 
-TEST_F('ChromeVoxLanguageSwitchingTest', 'AsturianTest', function() {
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_JapaneseAndKoreanUnlabeledDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.japaneseAndKoreanUnlabeledDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_switching_enabled_ = false;
+      // Node-level language detection runs and assigns language of 'ko' to the node.
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('ko', '한국어: 私は. 법률이 정하는 바에 의하여 대법관이 아닌 법관을 둘 수'
+            + ' 있다');
+      mockFeedback.replay();
+    });
+});
+
+
+TEST_F('ChromeVoxLanguageSwitchingTest', 'SubNodeLevelSwitching_AsturianAndJapaneseDoc_Test',
+  function() {
     var mockFeedback = this.createMockFeedback();
     this.runWithLoadedTree(this.asturianAndJapaneseDoc, function(root) {
       localStorage['languageSwitching'] = 'true';
@@ -339,9 +516,26 @@ TEST_F('ChromeVoxLanguageSwitchingTest', 'AsturianTest', function() {
     });
 });
 
+TEST_F('ChromeVoxLanguageSwitchingTest', 'NodeLevelSwitching_AsturianAndJapaneseDoc_Test',
+  function() {
+    var mockFeedback = this.createMockFeedback();
+    this.runWithLoadedTree(this.asturianAndJapaneseDoc, function(root) {
+      localStorage['languageSwitching'] = 'true';
+      LanguageSwitching.sub_node_level_switching_enabled_ = false;
+      mockFeedback.call(doCmd('jumpToTop'))
+          .expectSpeechWithLanguage('ja', '日本語: ど')
+          .call(doCmd('nextObject'))
+          .expectSpeechWithLanguage('ast', 'asturianu: Pretend that this text is Asturian. Testing'
+            + ' three-letter language code logic.');
+      mockFeedback.replay();
+    });
+});
+
+
+// This does not need partner tests because no language switching behavior is tested.
 TEST_F('ChromeVoxLanguageSwitchingTest', 'LanguageSwitchingOffTest', function() {
   var mockFeedback = this.createMockFeedback();
-  this.runWithLoadedTree(this.multipleLanguagesDoc, function(root) {
+  this.runWithLoadedTree(this.multipleLanguagesLabeledDoc, function(root) {
     localStorage['languageSwitching'] = 'false';
     // Language should not be set if the language switching feature is off.
     mockFeedback.call(doCmd('jumpToTop'))