wait_for_output utility function

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

@@ -8,12 +8,7 b' casper.notebook_test(function () {'
         cell.execute();
     });
 
-    this.waitFor(function () {
-        return this.evaluate(function get_output() {
-            var cell = IPython.notebook.get_cell(0);
-            return cell.output_area.outputs.length != 0;
-        })
-    });
+    this.wait_for_output(0);
 
     this.then(function () {
         var result = this.evaluate(function () {
@@ -33,12 +28,7 b' casper.notebook_test(function () {'
         IPython.utils.press_ctrl_enter();
     });
 
-    this.waitFor(function () {
-        return this.evaluate(function get_output() {
-            var cell = IPython.notebook.get_cell(0);
-            return cell.output_area.outputs.length != 0;
-        })
-    });
+    this.wait_for_output(0);
 
     this.then(function () {
         var result = this.evaluate(function () {
@@ -57,12 +47,7 b' casper.notebook_test(function () {'
         IPython.utils.press_shift_enter();
     });
 
-    this.waitFor(function () {
-        return this.evaluate(function get_output() {
-            var cell = IPython.notebook.get_cell(0);
-            return cell.output_area.outputs.length != 0;
-        })
-    });
+    this.wait_for_output(0);
 
     this.then(function () {
         var result = this.evaluate(function () {

IPython/html/tests/casperjs/util.js

@@ -54,6 +54,20 b' casper.delete_current_notebook = function () {'
     });
 };
 
+// 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});
+        });
+    });
+};
+
 // Wrap a notebook test to reduce boilerplate.
 casper.notebook_test = function(test) {
     this.open_new_notebook();