diff --git a/IPython/html/tests/casperjs/test_cases/widgets.js b/IPython/html/tests/casperjs/test_cases/widgets.js
index 2e06d48..296e659 100644
--- a/IPython/html/tests/casperjs/test_cases/widgets.js
+++ b/IPython/html/tests/casperjs/test_cases/widgets.js
@@ -77,7 +77,6 @@ casper.notebook_test(function () {
}
});
-
// Test bool widget ////////////////////////////////////////////////////////
var bool_index = this.append_cell(
'bool_widget = widgets.BoolWidget(description="Title", value=True)\n' +
@@ -882,4 +881,54 @@ casper.notebook_test(function () {
'.widget-area .widget-subarea div span.MathJax_Preview'),
'MathJax parsed the LaTeX successfully.');
});
+
+ // Test throttling /////////////////////////////////////////////////////////
+ throttle_index = this.append_cell(
+ 'import time\n' +
+ 'textbox = widgets.StringWidget()\n' +
+ 'display(textbox)\n'+
+ 'textbox.add_class("my-throttle-textbox")\n' +
+ 'def handle_change(name, old, new):\n' +
+ ' print(len(new))\n' +
+ ' time.sleep(0.5)\n' +
+ 'textbox.on_trait_change(handle_change)\n' +
+ 'print("Success")');
+ this.execute_cell_then(throttle_index, function(index){
+ this.test.assert(this.get_output_cell(index).text == 'Success\n',
+ 'Test throttling cell executed with correct output');
+
+ this.test.assert(this.cell_element_exists(index,
+ '.widget-area .widget-subarea'),
+ 'Widget subarea exists.');
+
+ this.test.assert(this.cell_element_exists(index,
+ '.my-throttle-textbox'), 'Textbox exists.');
+
+ // Send 20 characters
+ this.sendKeys('.my-throttle-textbox', '....................');
+ });
+
+ this.wait(2000); // Wait for clicks to execute in kernel
+
+ this.then(function(){
+ var resume = true;
+ var i = 0;
+ while (resume) {
+ i++;
+ var output = this.get_output_cell(throttle_index, i);
+ if (output === undefined || output === null) {
+ resume = false;
+ i--;
+ }
+ }
+
+ // Only 4 outputs should have printed, but because of timing, sometimes
+ // 5 outputs will print. All we need to do is verify num outputs <= 5
+ // because that is much less than 20.
+ this.test.assert(i <= 5, 'Messages throttled.');
+
+ // We also need to verify that the last state sent was correct.
+ var last_state = this.get_output_cell(throttle_index, i).text;
+ this.test.assert(last_state == "20\n", "Last state sent when throttling.");
+ })
});