Provide ability for WebUIBrowserTests to run asynchronous tests.

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 72de125013fd6830d488d5c1cb467aa5f679dd07..91a1aade01d26b4b920882071709414bfd542bf8 100644
--- a/chrome/test/data/webui/test_api.js
+++ b/chrome/test/data/webui/test_api.js
@@ -18,6 +18,17 @@ var testing = {};
  **/
 var currentTestCase = null;
 
+/**
+ * @type {?string} The string representation of the currently running test
+ *     function.
+ */
+var currentTestFunction = null;
+
+/**
+ * @type {?Array} The arguments of the currently running test.
+ */
+var currentTestArguments = null;
+
 (function() {
   // Provide global objects for generation case.
   if (this['window'] === undefined)
@@ -309,6 +320,43 @@ var currentTestCase = null;
    **/
   var helper = new CallHelper();
 
+  /**
+   * true when asyncTestDone has been called.
+   * @type {boolean}
+   */
+  var asyncTestIsDone = false;
+
+  /**
+   * Notifies the running browser test that any async javascript is complete.
+   * @param {Array.<boolean, string>=} result When passed, this is used for the
+   *     asyncTestResult message.
+   **/
+  function asyncTestDone(result) {
+    if (!asyncTestIsDone) {
+      asyncTestIsDone = true;
+      chrome.send('asyncTestResult', result ? result : testResult());
+    }
+  }
+
+  /**
+   * Returns [success, message] & clears |errors|.
+   * @return {Array.<boolean, string>}
+   **/
+  function testResult() {
+    var result = [true, ''];
+    if (errors.length) {
+      var message = '';
+      for (var i = 0; i < errors.length; ++i) {
+        message += 'Failed: ' + currentTestFunction + '(' +
+                   currentTestArguments.map(JSON.stringify) +
+                   ')\n' + errors[i].stack;
+      }
+      errors.splice(0, errors.length);
+      result = [false, message];
+    }
+    return result;
+  }
+
   // Asserts.
   // Use the following assertions to verify a condition within a test.
   // If assertion fails, the C++ backend will be immediately notified.
@@ -487,11 +535,12 @@ var currentTestCase = null;
     // 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.
-    if (typeof testBody === "undefined")
+    var testName = testFunction;
+    if (typeof testBody === "undefined") {
       testBody = eval(testFunction);
+      testName = testBody.toString();
+    }
     if (testBody != RUN_TEST_F) {
-      var testName =
-          testFunction.name ? testFunction.name : testBody.toString();
       console.log('Running test ' + testName);
     }
     return runTestFunction(testFunction, testBody, testArguments);
@@ -512,20 +561,10 @@ var currentTestCase = null;
    **/
   function runTestFunction(testFunction, testBody, testArguments) {
     errors.splice(0, errors.length);

[mmenke, 2011/08/05 16:08:28]

I'm still not sure about calling this here.  Seems to me that it makes the most
sense to clear the errors array right after results are reported, which would be
at the end of runTest (Which you currently don't do), and asyncTestDone (Which
you currently do).

[Sheridan Rawlins, 2011/08/05 16:59:56]

Wow, I just had the insight that this allows the call to runTestFunction to be
the "peek" we talked about.  It is a peek at the current state of errors in the
form of pass/fail + message. Moved the clearing to runTest and asyncTestDone,
where testResults (and hence runTestFunction) just returns the current results.

+    currentTestFunction = testFunction;
+    currentTestArguments = testArguments;
     createExpect(testBody).apply(null, testArguments);
-
-    var result = [true];
-    if (errors.length) {
-      var message = '';
-      for (var i = 0; i < errors.length; ++i) {
-        message += 'Failed: ' + testFunction + '(' +
-                   testArguments.map(JSON.stringify) +
-                   ')\n' + errors[i].stack;
-      }
-      errors.splice(0, errors.length);
-      result = [false, message];
-    }
-    return result;
+    return testResult();
   }
 
   /**
@@ -710,6 +749,7 @@ var currentTestCase = null;
 
   // Exports.
   testing.Test = Test;
+  window.asyncTestDone = asyncTestDone;
   window.assertTrue = assertTrue;
   window.assertFalse = assertFalse;
   window.assertGE = assertGE;