add checks for new cell added using shift-enter

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

@@ -13,7 +13,7 casper.notebook_test(function () {
     // refactor this into  just a get_output(0)
     this.then(function () {
         var result = this.get_output_cell(0);
-        this.test.assertEquals(result.text, '10\n', 'cell execute (using js)')
+        this.test.assertEquals(result.text, '10\n', 'cell execute (using js)');
     });
 
 
@@ -21,7 +21,7 casper.notebook_test(function () {
     this.thenEvaluate(function () {
         var cell = IPython.notebook.get_cell(0);
         cell.set_text('a=11; print(a)');
-        cell.clear_output()
+        cell.clear_output();
         IPython.utils.press_ctrl_enter();
     });
 
@@ -29,14 +29,16 casper.notebook_test(function () {
 
     this.then(function () {
         var result = this.get_output_cell(0);
-        this.test.assertEquals(result.text, '11\n', 'cell execute (using ctrl-enter)')
+        var num_cells = this.get_cells_length();
+        this.test.assertEquals(result.text, '11\n', 'cell execute (using ctrl-enter)');
+        this.test.assertEquals(num_cells, 1, '              ^--- does not add a new cell')
     });
     
     // do it again with the keyboard shortcut
     this.thenEvaluate(function () {
         var cell = IPython.notebook.get_cell(0);
         cell.set_text('a=12; print(a)');
-        cell.clear_output()
+        cell.clear_output();
         IPython.utils.press_shift_enter();
     });
 
@@ -44,6 +46,8 casper.notebook_test(function () {
 
     this.then(function () {
         var result = this.get_output_cell(0);
-        this.test.assertEquals(result.text, '12\n', 'cell execute (using shift-enter)')
+        var num_cells = this.get_cells_length();
+        this.test.assertEquals(result.text, '12\n', 'cell execute (using shift-enter)');
+        this.test.assertEquals(num_cells, 2, '              ^--- adds a new cell')
     });
 });

IPython/html/tests/casperjs/util.js

@@ -78,6 +78,14 casper.get_output_cell = function (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();