Add an accessibility audit test for WebUI pages

chrome/test/data/webui/test_api.js

Index: chrome/test/data/webui/test_api.js
diff --git a/chrome/test/data/webui/test_api.js b/chrome/test/data/webui/test_api.js
index 03c6721d51d55bf0baf4641caa2e6d9955c31802..5315213496cb072f1f26ba0a57030d43f4c7f107 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -122,6 +122,11 @@ var testing = {};
     extraLibraries: [],
 
     /**
+     * FIXME(aboxhall)
+     */
+    runA11yChecks: true,
+
+    /**
      * Create a new class to handle |messageNames|, assign it to
      * |this.mockHandler|, register its messages and return it.
      * @return {Mock} Mock handler class assigned to |this.mockHandler|.
@@ -234,6 +239,7 @@ var testing = {};
   function TestCase(name, fixture, body) {
     this.name = name;
     this.fixture = fixture;
+    this.runA11yChecks = fixture.runA11yChecks;
     this.body = body;
   }
 
@@ -264,6 +270,11 @@ var testing = {};
     deferred_: false,
 
     /**
+     * FIXME(aboxhall)
+     */
+    runA11yChecks: true,
+
+    /**
      * Called at preload time, proxies to the fixture.
      * @type {Function}
      */
@@ -585,6 +596,13 @@ var testing = {};
   var errors = [];
 
   /**
+   * Hold the accessibility warnings and errors, respectively.
+   * Like errors, cleared when results are reported.
+   */
+  var a11y_warnings = [];
+  var a11y_errors = [];
+
+  /**
    * URL to dummy WebUI page for testing framework.
    * @type {string}
    */
@@ -605,6 +623,9 @@ var testing = {};
    */
   function testDone(result) {
     if (!testIsDone) {
+      // FIXME(aboxhall): run a11y check if not disabled; combine with result.
+      var accessibilityOk = runAccessibilityAudit_(a11y_errors, a11y_warnings);
+
       testIsDone = true;
       if (currentTestCase) {
         try {
@@ -618,7 +639,12 @@ var testing = {};
         }
         currentTestCase = null;
       }
-      chrome.send('testResult', result ? result : testResult());
+      if (!result)
+        result = testResult();
+      if (!accessibilityOk)
+        result.push(createAccessibilityErrorMessage(a11y_errors,
+                                                    a11y_warnings));
+      chrome.send('testResult', result);
       errors.splice(0, errors.length);
     } else {
       console.warn('testIsDone already');
@@ -793,6 +819,66 @@ var testing = {};
   }
 
   /**
+   * FIXME(aboxhall) documentation
+   */
+  function createAccessibilityErrorMessage(a11y_errors, a11y_warnings) {
+    var errorMessage = 'Accessibility ';
+    if (a11y_errors.length > 0)
+      errorMessage += 'Errors ';
+    else
+      errorMessage += 'Warnings ';
+    errorMessage += 'found:\n';
+    for (var i = 0; i < a11y_errors.length; i++)
+      errorMessage += 'Error: ' + a11y_errors[i] + '\n';
+    for (var i = 0; i < a11y_warnings.length; i++)
+      errorMessage += 'Warning: ' + a11y_warnings[i] + '\n';
+    return errorMessage;
+  }
+
+  /**
+   * FIXME(aboxhall) documentation
+   */
+  function assertAccessibilityOk() {
+    helper.registerCall();
+    var a11y_errors = [];
+    var a11y_warnings = [];
+    if (!runAccessibilityAudit_(a11y_errors, a11y_warnings))
+      throw new Error(createAccessibilityErrorMessage(a11y_errors,
+                                                      a11y_warnings));
+  }
+
+  /**
+   * Run an accessibility audit on the current page state.
+   * FIXME(aboxhall) documentation
+   * @type {Function}
+   * @return {boolean} Whether there were any errors or warnings
+   * @private
+   */
+  function runAccessibilityAudit_(errors, warnings) {
+    for (var auditRuleName in axs.AuditRule.specs) {
+      var auditRule = axs.AuditRules.getRule(auditRuleName);
+      if (!auditRule)
+        continue; // Shouldn't happen, but fail silently if it does.
+      if (!auditRule.disabled && !auditRule.requiresConsoleAPI) {
+        var result = auditRule.run();
+          if (result.result == axs.constants.AuditResult.FAIL) {
+          // TODO(aboxhall): more useful error messages (sadly non-trivial)
+          if (auditRule.severity == axs.constants.Severity.Severe)
+            errors.push("Accessibility audit rule " + auditRule.name +
+                        " failed");
+          else
+            warnings.push("Accessibility audit rule " + auditRule.name +
+                          " failed");
+        }
+      }
+    }
+    // TODO(aboxhall): have strict (no errors or warnings) vs non-strict
+    // (warnings ok)
+    // TODO(aboxhall): some kind of info logging for warnings only??
+    return (errors.length == 0 && warnings.length == 0);
+  }
+
+  /**
    * Creates a function based upon a function that thows an exception on
    * failure. The new function stuffs any errors into the |errors| array for
    * checking by runTest. This allows tests to continue running other checks,
@@ -834,6 +920,7 @@ var testing = {};
    * @see runTestFunction
    */
   function runTest(isAsync, testFunction, testArguments) {
+    // FIXME(aboxhall): modify to add a11y phase
     // Avoid eval() if at all possible, since it will not work on pages
     // that have enabled content-security-policy.
     var testBody = this[testFunction];    // global object -- not a method.
@@ -1389,6 +1476,7 @@ var testing = {};
   exports.expectLT = createExpect(assertLT);
   exports.expectNotEquals = createExpect(assertNotEquals);
   exports.expectNotReached = createExpect(assertNotReached);
+  exports.expectAccessibilityOk = createExpect(assertAccessibilityOk);
   exports.preloadJavascriptLibraries = preloadJavascriptLibraries;
   exports.registerMessageCallback = registerMessageCallback;
   exports.registerMockGlobals = registerMockGlobals;