Add regression tests for live notebook

IPython/html/tests/notebook/prompt_numbers.js

@@ -0,0 +1,36
+
+// Test
+casper.notebook_test(function () {
+
+    var that = this;
+    var set_prompt = function (i, val) {
+        that.evaluate(function (i, val) {
+            var cell = IPython.notebook.get_cell(i);
+            cell.set_input_prompt(val);
+        }, [i, val]);
+    };
+
+    var get_prompt = function (i) {
+        return that.evaluate(function (i) {
+            var elem = IPython.notebook.get_cell(i).element;
+            return elem.find('div.input_prompt').html();
+        }, [i]);
+    };
+
+    this.then(function () {
+        var a = 'print("a")';
+        var index = this.append_cell(a);
+
+        this.test.assertEquals(get_prompt(index), "In [ ]:", "prompt number is   by default");
+        set_prompt(index, 2);
+        this.test.assertEquals(get_prompt(index), "In [2]:", "prompt number is 2");
+        set_prompt(index, 0);
+        this.test.assertEquals(get_prompt(index), "In [0]:", "prompt number is 0");
+        set_prompt(index, "*");
+        this.test.assertEquals(get_prompt(index), "In [*]:", "prompt number is *");
+        set_prompt(index, undefined);
+        this.test.assertEquals(get_prompt(index), "In [ ]:", "prompt number is  ");
+        set_prompt(index, null);
+        this.test.assertEquals(get_prompt(index), "In [ ]:", "prompt number is  ");
+    });
+});