wait for new-notebook button to arrive

before clicking it.

Race condition was causing intermittent test failures.

IPython/html/tests/util.js

@@ -1,831 +1,832
 //
 // Utility functions for the HTML notebook's CasperJS tests.
 //
 casper.get_notebook_server = function () {
     // Get the URL of a notebook server on which to run tests.
     var port = casper.cli.get("port");
     port = (typeof port === 'undefined') ? '8888' : port;
     return casper.cli.get("url") || ('http://127.0.0.1:' + port);
 };
 
 casper.open_new_notebook = function () {
     // Create and open a new notebook.
     var baseUrl = this.get_notebook_server();
     this.start(baseUrl);
     this.waitFor(this.page_loaded);
+    this.waitForSelector('#kernel-python2 a, #kernel-python3 a');
     this.thenClick('#kernel-python2 a, #kernel-python3 a');
     
     this.waitForPopup('');
 
     this.withPopup('', function () {this.waitForSelector('.CodeMirror-code');});
     this.then(function () {
         this.open(this.popups[0].url);
     });
     this.waitFor(this.page_loaded);
 
     // Hook the log and error methods of the console, forcing them to
     // serialize their arguments before printing.  This allows the
     // Objects to cross into the phantom/slimer regime for display.
     this.thenEvaluate(function(){
         var serialize_arguments = function(f, context) {
             return function() {
                 var pretty_arguments = [];
                 for (var i = 0; i < arguments.length; i++) {
                     var value = arguments[i];
                     if (value instanceof Object) {
                         var name = value.name || 'Object';
                         // Print a JSON string representation of the object.
                         // If we don't do this, [Object object] gets printed
                         // by casper, which is useless.  The long regular
                         // expression reduces the verbosity of the JSON.
                         pretty_arguments.push(name + ' {' + JSON.stringify(value, null, '  ')
                             .replace(/(\s+)?({)?(\s+)?(}(\s+)?,?)?(\s+)?(\s+)?\n/g, '\n')
                             .replace(/\n(\s+)?\n/g, '\n'));
                     } else {
                         pretty_arguments.push(value);
                     }
                 }
                 f.apply(context, pretty_arguments);
             };
         };
         console.log = serialize_arguments(console.log, console);
         console.error = serialize_arguments(console.error, console);
     });
 
     // Make sure the kernel has started
     this.waitFor(this.kernel_running);
     // track the IPython busy/idle state
     this.thenEvaluate(function () {
         require(['base/js/namespace', 'base/js/events'], function (IPython, events) {
         
             events.on('kernel_idle.Kernel',function () {
                 IPython._status = 'idle';
             });
             events.on('kernel_busy.Kernel',function () {
                 IPython._status = 'busy';
             });
         });
     });
 
     // Because of the asynchronous nature of SlimerJS (Gecko), we need to make
     // sure the notebook has actually been loaded into the IPython namespace
     // before running any tests.
     this.waitFor(function() {
         return this.evaluate(function () {
             return IPython.notebook;
         });
     });
 };
 
 casper.page_loaded = function() {
     // Return whether or not the kernel is running.
     return this.evaluate(function() {
         return typeof IPython !== "undefined" &&
             IPython.page !== undefined;
     });
 };
 
 casper.kernel_running = function() {
     // Return whether or not the kernel is running.
     return this.evaluate(function() {
         return IPython &&
         IPython.notebook &&
         IPython.notebook.kernel &&
         IPython.notebook.kernel.is_connected();
     });
 };
 
 casper.kernel_disconnected = function() {
     return this.evaluate(function() {
         return IPython.notebook.kernel.is_fully_disconnected();
     });
 };
 
 casper.wait_for_kernel_ready = function () {
     this.waitFor(this.kernel_running);
     this.thenEvaluate(function () {
         IPython._kernel_ready = false;
         IPython.notebook.kernel.kernel_info(
             function () {
                 IPython._kernel_ready = true;
             });
     });
     this.waitFor(function () {
         return this.evaluate(function () {
             return IPython._kernel_ready;
         });
     });
 };
 
 casper.shutdown_current_kernel = function () {
     // Shut down the current notebook's kernel.
     this.thenEvaluate(function() {
         IPython.notebook.session.delete();
     });
     // We close the page right after this so we need to give it time to complete.
     this.wait(1000);
 };
 
 casper.delete_current_notebook = function () {
     // Delete created notebook.
 
     // For some unknown reason, this doesn't work?!?
     this.thenEvaluate(function() {
         IPython.notebook.delete();
     });
 };
 
 casper.wait_for_busy = function () {
     // Waits for the notebook to enter a busy state.
     this.waitFor(function () {
         return this.evaluate(function () {
             return IPython._status == 'busy';
         });
     });
 };
 
 casper.wait_for_idle = function () {
     // Waits for the notebook to idle.
     this.waitFor(function () {
         return this.evaluate(function () {
             return IPython._status == 'idle';
         });
     });
 };
 
 casper.wait_for_output = function (cell_num, out_num) {
     // wait for the nth output in a given cell
     this.wait_for_idle();
     out_num = out_num || 0;
     this.then(function() {
         this.waitFor(function (c, o) {
             return this.evaluate(function get_output(c, o) {
                 var cell = IPython.notebook.get_cell(c);
                 return cell.output_area.outputs.length > o;
             },
             // pass parameter from the test suite js to the browser code js
             {c : cell_num, o : out_num});
         });
     },
     function then() { },
     function timeout() {
         this.echo("wait_for_output timed out!");
     });
 };
 
 casper.wait_for_widget = function (widget_info) {
     // wait for a widget msg que to reach 0
     //
     // Parameters
     // ----------
     // widget_info : object
     //      Object which contains info related to the widget.  The model_id property
     //      is used to identify the widget.
 
     // Clear the results of a previous query, if they exist.  Make sure a
     // dictionary exists to store the async results in.
     this.thenEvaluate(function(model_id) {
         if (window.pending_msgs === undefined) { 
             window.pending_msgs = {}; 
         } else {
             window.pending_msgs[model_id] = -1;
         } 
     }, {model_id: widget_info.model_id});
 
     // Wait for the pending messages to be 0.
     this.waitFor(function () {
         var pending = this.evaluate(function (model_id) {
 
             // Get the model.  Once the model is had, store it's pending_msgs
             // count in the window's dictionary.
             IPython.notebook.kernel.widget_manager.get_model(model_id)
             .then(function(model) {     
                 window.pending_msgs[model_id] = model.pending_msgs; 
             });
 
             // Return the pending_msgs result.
             return window.pending_msgs[model_id];
         }, {model_id: widget_info.model_id});
 
         if (pending === 0) {
             return true;
         } else {
             return false;
         }
     });
 };
 
 casper.get_output_cell = function (cell_num, out_num) {
     // return an output of a given cell
     out_num = out_num || 0;
     var result = casper.evaluate(function (c, o) {
         var cell = IPython.notebook.get_cell(c);
         return cell.output_area.outputs[o];
     },
     {c : cell_num, o : out_num});
     if (!result) {
         var num_outputs = casper.evaluate(function (c) {
             var cell = IPython.notebook.get_cell(c);
             return cell.output_area.outputs.length;
         },
         {c : cell_num});
         this.test.assertTrue(false,
             "Cell " + cell_num + " has no output #" + out_num + " (" + num_outputs + " total)"
         );
     } else {
         return result;
     }
 };
 
 casper.get_cells_length = function () {
     // return the number of cells in the notebook
     var result = casper.evaluate(function () {
         return IPython.notebook.get_cells().length;
     });
     return result;
 };
 
 casper.set_cell_text = function(index, text){
     // Set the text content of a cell.
     this.evaluate(function (index, text) {
         var cell = IPython.notebook.get_cell(index);
         cell.set_text(text);
     }, index, text);
 };
 
 casper.get_cell_text = function(index){
     // Get the text content of a cell.
     return this.evaluate(function (index) {
         var cell = IPython.notebook.get_cell(index);
         return cell.get_text();
     }, index);
 };
 
 casper.insert_cell_at_bottom = function(cell_type){
     // Inserts a cell at the bottom of the notebook
     // Returns the new cell's index.
     return this.evaluate(function (cell_type) {
         var cell = IPython.notebook.insert_cell_at_bottom(cell_type);
         return IPython.notebook.find_cell_index(cell);
     }, cell_type);
 };
 
 casper.append_cell = function(text, cell_type) { 
     // Insert a cell at the bottom of the notebook and set the cells text.
     // Returns the new cell's index.
     var index = this.insert_cell_at_bottom(cell_type);
     if (text !== undefined) {
         this.set_cell_text(index, text);
     }
     return index;
 };
 
 casper.execute_cell = function(index, expect_failure){
     // Asynchronously executes a cell by index.
     // Returns the cell's index.
     
     if (expect_failure === undefined) expect_failure = false;
     var that = this;
     this.then(function(){
         that.evaluate(function (index) {
             var cell = IPython.notebook.get_cell(index);
             cell.execute();
         }, index);
     });
     this.wait_for_idle();
     
     this.then(function () {
         var error = that.evaluate(function (index) {
             var cell = IPython.notebook.get_cell(index);
             var outputs = cell.output_area.outputs;
             for (var i = 0; i < outputs.length; i++) {
                 if (outputs[i].output_type == 'error') {
                     return outputs[i];
                 }
             }
             return false;
         }, index);
         if (error === null) {
             this.test.fail("Failed to check for error output");
         }
         if (expect_failure && error === false) {
             this.test.fail("Expected error while running cell");
         } else if (!expect_failure && error !== false) {
             this.test.fail("Error running cell:\n" + error.traceback.join('\n'));
         }
     });
     return index;
 };
 
 casper.execute_cell_then = function(index, then_callback, expect_failure) {
     // Synchronously executes a cell by index.
     // Optionally accepts a then_callback parameter.  then_callback will get called
     // when the cell  has finished executing.
     // Returns the cell's index.
     var return_val = this.execute_cell(index, expect_failure);
 
     this.wait_for_idle();
 
     var that = this;
     this.then(function(){ 
         if (then_callback!==undefined) {
             then_callback.apply(that, [index]);
         }
     });
 
     return return_val;
 };
 
 casper.wait_for_element = function(index, selector){
     // Utility function that allows us to easily wait for an element 
     // within a cell.  Uses JQuery selector to look for the element.
     var that = this;
     this.waitFor(function() {
         return that.cell_element_exists(index, selector);
     });
 };
 
 casper.cell_element_exists = function(index, selector){
     // Utility function that allows us to easily check if an element exists 
     // within a cell.  Uses JQuery selector to look for the element.
     return casper.evaluate(function (index, selector) {
         var $cell = IPython.notebook.get_cell(index).element;
         return $cell.find(selector).length > 0;
     }, index, selector);
 };
 
 casper.cell_element_function = function(index, selector, function_name, function_args){
     // Utility function that allows us to execute a jQuery function on an 
     // element within a cell.
     return casper.evaluate(function (index, selector, function_name, function_args) {
         var $cell = IPython.notebook.get_cell(index).element;
         var $el = $cell.find(selector);
         return $el[function_name].apply($el, function_args);
     }, index, selector, function_name, function_args);
 };
 
 casper.validate_notebook_state = function(message, mode, cell_index) {
     // Validate the entire dual mode state of the notebook.  Make sure no more than
     // one cell is selected, focused, in edit mode, etc...
 
     // General tests.
     this.test.assertEquals(this.get_keyboard_mode(), this.get_notebook_mode(),
         message + '; keyboard and notebook modes match');
     // Is the selected cell the only cell that is selected?
     if (cell_index!==undefined) {
         this.test.assert(this.is_only_cell_selected(cell_index),
             message + '; cell ' + cell_index + ' is the only cell selected');
     }
 
     // Mode specific tests.
     if (mode==='command') {
         // Are the notebook and keyboard manager in command mode?
         this.test.assertEquals(this.get_keyboard_mode(), 'command',
             message + '; in command mode');
         // Make sure there isn't a single cell in edit mode.
         this.test.assert(this.is_only_cell_edit(null),
             message + '; all cells in command mode');
         this.test.assert(this.is_cell_editor_focused(null),
             message + '; no cell editors are focused while in command mode');
 
     } else if (mode==='edit') {
         // Are the notebook and keyboard manager in edit mode?
         this.test.assertEquals(this.get_keyboard_mode(), 'edit',
             message + '; in edit mode');
         if (cell_index!==undefined) {
             // Is the specified cell the only cell in edit mode?
             this.test.assert(this.is_only_cell_edit(cell_index),
                 message + '; cell ' + cell_index + ' is the only cell in edit mode '+ this.cells_modes());
             // Is the specified cell the only cell with a focused code mirror?
             this.test.assert(this.is_cell_editor_focused(cell_index),
                 message + '; cell ' + cell_index + '\'s editor is appropriately focused');
         }
 
     } else {
         this.test.assert(false, message + '; ' + mode + ' is an unknown mode');
     }
 };
 
 casper.select_cell = function(index) {
     // Select a cell in the notebook.
     this.evaluate(function (i) {
         IPython.notebook.select(i);
     }, {i: index});
 };
 
 casper.click_cell_editor = function(index) {
     // Emulate a click on a cell's editor.
     
     // Code Mirror does not play nicely with emulated brower events.  
     // Instead of trying to emulate a click, here we run code similar to
     // the code used in Code Mirror that handles the mousedown event on a
     // region of codemirror that the user can focus.
     this.evaluate(function (i) {
         var cm = IPython.notebook.get_cell(i).code_mirror;
         if (cm.options.readOnly != "nocursor" && (document.activeElement != cm.display.input)){
             cm.display.input.focus();
         }
     }, {i: index});
 };
 
 casper.set_cell_editor_cursor = function(index, line_index, char_index) {
     // Set the Code Mirror instance cursor's location.
     this.evaluate(function (i, l, c) {
         IPython.notebook.get_cell(i).code_mirror.setCursor(l, c);
     }, {i: index, l: line_index, c: char_index});
 };
 
 casper.focus_notebook = function() {
     // Focus the notebook div.
     this.evaluate(function (){
         $('#notebook').focus();
     }, {});
 };
 
 casper.trigger_keydown = function() {
     // Emulate a keydown in the notebook.
     for (var i = 0; i < arguments.length; i++) {
         this.evaluate(function (k) {
             var element = $(document);
             var event = IPython.keyboard.shortcut_to_event(k, 'keydown');
             element.trigger(event);
         }, {k: arguments[i]});    
     }
 };
 
 casper.get_keyboard_mode = function() {
     // Get the mode of the keyboard manager.
     return this.evaluate(function() {
         return IPython.keyboard_manager.mode;
     }, {});
 };
 
 casper.get_notebook_mode = function() {
     // Get the mode of the notebook.
     return this.evaluate(function() {
         return IPython.notebook.mode;
     }, {});
 };
 
 casper.get_cell = function(index) {
     // Get a single cell.
     //
     // Note: Handles to DOM elements stored in the cell will be useless once in
     //       CasperJS context.
     return this.evaluate(function(i) {
         var cell = IPython.notebook.get_cell(i);
         if (cell) {
             return cell;
         }
         return null;
     }, {i : index});
 };
 
 casper.is_cell_editor_focused = function(index) {
     // Make sure a cell's editor is the only editor focused on the page.
     return this.evaluate(function(i) {
         var focused_textarea = $('#notebook .CodeMirror-focused textarea');
         if (focused_textarea.length > 1) { throw 'More than one Code Mirror editor is focused at once!'; }
         if (i === null) {
             return focused_textarea.length === 0;
         } else {
             var cell = IPython.notebook.get_cell(i);
             if (cell) {
                 return cell.code_mirror.getInputField() == focused_textarea[0];
             }    
         }
         return false;
     }, {i : index});
 };
 
 casper.is_only_cell_selected = function(index) {
     // Check if a cell is the only cell selected.
     // Pass null as the index to check if no cells are selected.
     return this.is_only_cell_on(index, 'selected', 'unselected');
 };
 
 casper.is_only_cell_edit = function(index) {
     // Check if a cell is the only cell in edit mode.
     // Pass null as the index to check if all of the cells are in command mode.
     var cells_length = this.get_cells_length();
     for (var j = 0; j < cells_length; j++) {
         if (j === index) {
             if (!this.cell_mode_is(j, 'edit')) {
                 return false;
             }
         } else {
             if (this.cell_mode_is(j, 'edit')) {
                 return false;
             }
         }
     }
     return true;
 };
 
 casper.is_only_cell_on = function(i, on_class, off_class) {
     // Check if a cell is the only cell with the `on_class` DOM class applied to it.
     // All of the other cells are checked for the `off_class` DOM class.
     // Pass null as the index to check if all of the cells have the `off_class`.
     var cells_length = this.get_cells_length();
     for (var j = 0; j < cells_length; j++) {
         if (j === i) {
             if (this.cell_has_class(j, off_class) || !this.cell_has_class(j, on_class)) {
                 return false;
             }
         } else {
             if (!this.cell_has_class(j, off_class) || this.cell_has_class(j, on_class)) {
                 return false;
             }
         }
     }
     return true;
 };
 
 casper.cells_modes = function(){
     return this.evaluate(function(){
         return IPython.notebook.get_cells().map(function(x,c){return x.mode})
     }, {});
 };
 
 casper.cell_mode_is = function(index, mode) {
     // Check if a cell is in a specific mode
     return this.evaluate(function(i, m) {
         var cell = IPython.notebook.get_cell(i);
         if (cell) {
             return cell.mode === m;
         }
         return false;
     }, {i : index, m: mode});
 };
 
 
 casper.cell_has_class = function(index, classes) {
     // Check if a cell has a class.
     return this.evaluate(function(i, c) {
         var cell = IPython.notebook.get_cell(i);
         if (cell) {
             return cell.element.hasClass(c);
         }
         return false;
     }, {i : index, c: classes});
 };
 
 casper.is_cell_rendered = function (index) {
     return this.evaluate(function(i) {
         return !!IPython.notebook.get_cell(i).rendered;
     }, {i:index});
 };
 
 casper.assert_colors_equal = function (hex_color, local_color, msg) {
     // Tests to see if two colors are equal.
     //
     // Parameters
     // hex_color: string
     //      Hexadecimal color code, with or without preceeding hash character.
     // local_color: string
     //      Local color representation.  Can either be hexadecimal (default for 
     //      phantom) or rgb (default for slimer).
 
     // Remove parentheses, hashes, semi-colons, and space characters.
     hex_color = hex_color.replace(/[\(\); #]/, '');
     local_color = local_color.replace(/[\(\); #]/, '');
 
     // If the local color is rgb, clean it up and replace 
     if (local_color.substr(0,3).toLowerCase() == 'rgb') {
         var components = local_color.substr(3).split(',');
         local_color = '';
         for (var i = 0; i < components.length; i++) {
             var part = parseInt(components[i]).toString(16);
             while (part.length < 2) part = '0' + part;
             local_color += part;
         }
     }
     
     this.test.assertEquals(hex_color.toUpperCase(), local_color.toUpperCase(), msg);
 };
 
 casper.notebook_test = function(test) {
     // Wrap a notebook test to reduce boilerplate.
     this.open_new_notebook();
 
     // Echo whether or not we are running this test using SlimerJS
     if (this.evaluate(function(){
         return typeof InstallTrigger !== 'undefined';   // Firefox 1.0+
     })) { 
         console.log('This test is running in SlimerJS.'); 
         this.slimerjs = true;
     }
     
     // Make sure to remove the onbeforeunload callback.  This callback is 
     // responsible for the "Are you sure you want to quit?" type messages.
     // PhantomJS ignores these prompts, SlimerJS does not which causes hangs.
     this.then(function(){
         this.evaluate(function(){
             window.onbeforeunload = function(){};
         });
     });
 
     this.then(test);
     
     // Kill the kernel and delete the notebook.
     this.shutdown_current_kernel();
     // This is still broken but shouldn't be a problem for now.
     // this.delete_current_notebook();
     
     // This is required to clean up the page we just finished with. If we don't call this
     // casperjs will leak file descriptors of all the open WebSockets in that page. We
     // have to set this.page=null so that next time casper.start runs, it will create a
     // new page from scratch.
     this.then(function () {
         this.page.close();
         this.page = null;
     });
     
     // Run the browser automation.
     this.run(function() {
         this.test.done();
     });
 };
 
 casper.wait_for_dashboard = function () {
     // Wait for the dashboard list to load.
     casper.waitForSelector('.list_item');
 };
 
 casper.open_dashboard = function () {
     // Start casper by opening the dashboard page.
     var baseUrl = this.get_notebook_server();
     this.start(baseUrl);
     this.waitFor(this.page_loaded);
     this.wait_for_dashboard();
 };
 
 casper.dashboard_test = function (test) {
     // Open the dashboard page and run a test.
     this.open_dashboard();
     this.then(test);
 
     this.then(function () {
         this.page.close();
         this.page = null;
     });
     
     // Run the browser automation.
     this.run(function() {
         this.test.done();
     });
 };
 
 // note that this will only work for UNIQUE events -- if you want to
 // listen for the same event twice, this will not work!
 casper.event_test = function (name, events, action, timeout) {
 
     // set up handlers to listen for each of the events
     this.thenEvaluate(function (events) {
         var make_handler = function (event) {
             return function () {
                 IPython._events_triggered.push(event);
                 IPython.notebook.events.off(event, null, IPython._event_handlers[event]);
                 delete IPython._event_handlers[event];
             };
         };
         IPython._event_handlers = {};
         IPython._events_triggered = [];
         for (var i=0; i < events.length; i++) {
             IPython._event_handlers[events[i]] = make_handler(events[i]);
             IPython.notebook.events.on(events[i], IPython._event_handlers[events[i]]);
         }
     }, [events]);
 
     // execute the requested action
     this.then(action);
 
     // wait for all the events to be triggered
     this.waitFor(function () {
         return this.evaluate(function (events) {
             return IPython._events_triggered.length >= events.length;
         }, [events]);
     }, undefined, undefined, timeout);
 
     // test that the events were triggered in the proper order
     this.then(function () {
         var triggered = this.evaluate(function () {
             return IPython._events_triggered;
         });
         var handlers = this.evaluate(function () {
             return Object.keys(IPython._event_handlers);
         });
         this.test.assertEquals(triggered.length, events.length, name + ': ' + events.length + ' events were triggered');
         this.test.assertEquals(handlers.length, 0, name + ': all handlers triggered');
         for (var i=0; i < events.length; i++) {
             this.test.assertEquals(triggered[i], events[i], name + ': ' + events[i] + ' was triggered');
         }
     });
 
     // turn off any remaining event listeners
     this.thenEvaluate(function () {
         for (var event in IPython._event_handlers) {
             IPython.notebook.events.off(event, null, IPython._event_handlers[event]);
             delete IPython._event_handlers[event];
         }
     });
 };
 
 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?");
 });
 
 casper.print_log = function () {
     // Pass `console.log` calls from page JS to casper.
     this.on('remote.message', function(msg) {
         this.echo('Remote message caught: ' + msg);
     });
 };
 
 casper.on("page.error", function onError(msg, trace) {
     // show errors in the browser
     this.echo("Page Error");
     this.echo("  Message:   " + msg.split('\n').join('\n             '));
     this.echo("  Call stack:");
     var local_path = this.get_notebook_server();
     for (var i = 0; i < trace.length; i++) {
         var frame = trace[i];
         var file = frame.file;
         // shorten common phantomjs evaluate url
         // this will have a different value on slimerjs
         if (file === "phantomjs://webpage.evaluate()") {
             file = "evaluate";
         }
         // remove the version tag from the path
         file = file.replace(/(\?v=[0-9abcdef]+)/, '');
         // remove the local address from the beginning of the path
         if (file.indexOf(local_path) === 0) {
             file = file.substr(local_path.length);
         }
         var frame_text = (frame.function.length > 0) ? " in " + frame.function : "";
         this.echo("    line " + frame.line + " of " + file + frame_text);
     }
 });
 
 
 casper.capture_log = function () {
     // show captured errors
     var captured_log = [];
     var seen_errors = 0;
     this.on('remote.message', function(msg) {
         captured_log.push(msg);
     });
 
     var that = this;
     this.test.on("test.done", function (result) {
         // test.done runs per-file,
         // but suiteResults is per-suite (directory)
         var current_errors;
         if (this.suiteResults) {
             // casper 1.1 has suiteResults
             current_errors = this.suiteResults.countErrors() + this.suiteResults.countFailed();
         } else {
             // casper 1.0 has testResults instead
             current_errors = this.testResults.failed;
         }
 
         if (current_errors > seen_errors && captured_log.length > 0) {
             casper.echo("\nCaptured console.log:");
             for (var i = 0; i < captured_log.length; i++) {
                 var output = String(captured_log[i]).split('\n');
                 for (var j = 0; j < output.length; j++) {
                     casper.echo("    " + output[j]);
                 }
             }
         }
 
         seen_errors = current_errors;
         captured_log = [];
     });
 };
 
 casper.interact = function() {
     // Start an interactive Javascript console.
     var system = require('system');
     system.stdout.writeLine('JS interactive console.');
     system.stdout.writeLine('Type `exit` to quit.');
 
     function read_line() {
         system.stdout.writeLine('JS: ');
         var line = system.stdin.readLine();
         return line;
     }
 
     var input = read_line();
     while (input.trim() != 'exit') {
         var output = this.evaluate(function(code) {
             return String(eval(code));
         }, {code: input});
         system.stdout.writeLine('\nOut: ' + output);
         input = read_line();
     }
 };
 
 casper.capture_log();