yet another JS race condition fix

this should greatly reduce the number of timeouts seen in the JS tests

IPython/html/tests/casperjs/test_cases/check_interrupt.js

@@ -1,39 +1,49 b''
 //
 // Test kernel interrupt 
 //
 casper.notebook_test(function () {
     this.evaluate(function () {
         var cell = IPython.notebook.get_cell(0);
-        cell.set_text('import time\nfor x in range(3):\n    time.sleep(1)');
+        cell.set_text(
+            'import time'+
+            '\nfor x in range(3):'+
+            '\n    time.sleep(1)'
+            );
         cell.execute();
     });
 
+    this.waitFor(function(){
+        return this.evaluate(function() {
+            return $("#notification_kernel")[0].textContent.indexOf('busy') !== -1;
+        });
+    });
+
 
     // interrupt using menu item (Kernel -> Interrupt)
     this.thenClick('li#int_kernel');
 
     this.wait_for_output(0);
 
     this.then(function () {
         var result = this.get_output_cell(0);
         this.test.assertEquals(result.ename, 'KeyboardInterrupt', 'keyboard interrupt (mouseclick)');
     });
 
     // run cell 0 again, now interrupting using keyboard shortcut
     this.thenEvaluate(function () {
         cell.clear_output();
         cell.execute();
     });
 
     // interrupt using Ctrl-M I keyboard shortcut
     this.thenEvaluate( function() {
         IPython.utils.press_ghetto(IPython.utils.keycodes.I)
     });
     
     this.wait_for_output(0);
     
     this.then(function () {
         var result = this.get_output_cell(0);
         this.test.assertEquals(result.ename, 'KeyboardInterrupt', 'keyboard interrupt (shortcut)');
     });
 });

IPython/html/tests/casperjs/util.js

@@ -1,123 +1,127 b''
 //
 // Utility functions for the HTML notebook's CasperJS tests.
 //
 
 // Get the URL of a notebook server on which to run tests.
 casper.get_notebook_server = function () {
     port = casper.cli.get("port")
     port = (typeof port === 'undefined') ? '8888' : port;
     return 'http://127.0.0.1:' + port
 };
 
 // Create and open a new notebook.
 casper.open_new_notebook = function () {
     var baseUrl = this.get_notebook_server();
     this.start(baseUrl);
     this.thenClick('button#new_notebook');
     this.waitForPopup('');
 
     this.withPopup('', function () {this.waitForSelector('.CodeMirror-code');});
     this.then(function () {
         // XXX: Kind of odd, the next line works for one test, but not when
         // running multiple tests back-to-back, so we will just point the main
         // casper browser to the same URL as the popup we just grabbed.
 
         //this.page = this.popups[0];
         this.open(this.popups[0].url);
     });
 
     // initially, the cells aren't created, so wait for them to appear
     this.waitForSelector('.CodeMirror-code');
     // and make sure the kernel has started
     this.waitFor( this.kernel_running  );
 };
 
 // return whether or not the kernel is running
 casper.kernel_running = function kernel_running() {
     return this.evaluate(function kernel_running() {
         return IPython.notebook.kernel.running;
     });
 };
 
 // Shut down the current notebook's kernel.
 casper.shutdown_current_kernel = function () {
     this.thenEvaluate(function() {
         IPython.notebook.kernel.kill();
     });
 };
 
 // Delete created notebook.
 casper.delete_current_notebook = function () {
     this.thenEvaluate(function() {
         var nbData = $('body').data();
         var url = nbData.baseProjectUrl + 'notebooks/' + nbData.notebookId;
         $.ajax(url, {
             type: 'DELETE',
         });
     });
 };
 
 // wait for output in a given cell
 casper.wait_for_output = function (cell_num) {
     this.then(function() {
         this.waitFor(function (c) {
             return this.evaluate(function get_output(c) {
                 var cell = IPython.notebook.get_cell(c);
                 return cell.output_area.outputs.length != 0;
             },
             // pass parameter from the test suite js to the browser code js
             {c : cell_num});
+        },
+        function then() { },
+        function timeout() {
+            this.echo("wait_for_output timedout!");
         });
     });
 };
 
 // return the output of a given cell
 casper.get_output_cell = function (cell_num) {
     var result = casper.evaluate(function (c) {
         var cell = IPython.notebook.get_cell(c);
         return cell.output_area.outputs[0];
     },
     {c : cell_num});
     return result;
 };
 
 // return the number of cells in the notebook
 casper.get_cells_length = function () {
     var result = casper.evaluate(function () {
         return IPython.notebook.get_cells().length;
     })
     return result;
 };
 
 // Wrap a notebook test to reduce boilerplate.
 casper.notebook_test = function(test) {
     this.open_new_notebook();
     this.then(test);
     //XXX: we get sporadic error messages when shutting down some of the tests.
     //     Since the entire server will go down at the end of running the test
     //     suite, it's ok for now to not try to shut anything down.
     this.shutdown_current_kernel();
     
     //XXX: the implementation of delete_current_notebook is currently broken
     //     it's not a big deal, since the notebook directory will be deleted on
     //     cleanup, but we should add tests for deleting the notebook separately
     //this.delete_current_notebook();
     
     // Run the browser automation.
     this.run(function() {
         this.test.done();
     });
 };
 
 casper.options.waitTimeout=10000
 casper.on('waitFor.timeout', function onWaitForTimeout(timeout) {
     this.echo("Timeout for " + casper.get_notebook_server());
     this.echo("Is the notebook server running?");
 });
 
 // Pass `console.log` calls from page JS to casper.
 casper.printLog = function () {
     this.on('remote.message', function(msg) {
         this.echo('Remote message caught: ' + msg);
     });
 };