diff -r 000000000000 -r 6474c204b198 browser/devtools/sourceeditor/test/browser_editor_basic.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/sourceeditor/test/browser_editor_basic.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,62 @@
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+function test() {
+  waitForExplicitFinish();
+  setup((ed, win) => {
+    // appendTo
+    let src = win.document.querySelector("iframe").getAttribute("src");
+    ok(~src.indexOf(".CodeMirror"), "correct iframe is there");
+
+    // getOption/setOption
+    ok(ed.getOption("styleActiveLine"), "getOption works");
+    ed.setOption("styleActiveLine", false);
+    ok(!ed.getOption("styleActiveLine"), "setOption works");
+
+    // Language modes
+    is(ed.getMode(), Editor.modes.text, "getMode");
+    ed.setMode(Editor.modes.js);
+    is(ed.getMode(), Editor.modes.js, "setMode");
+
+    // Content
+    is(ed.getText(), "Hello.", "getText");
+    ed.setText("Hi.\nHow are you?");
+    is(ed.getText(), "Hi.\nHow are you?", "setText");
+    is(ed.getText(1), "How are you?", "getText(num)");
+    is(ed.getText(5), "", "getText(num) when num is out of scope");
+
+    ed.replaceText("YOU", { line: 1, ch: 8 }, { line: 1, ch: 11 });
+    is(ed.getText(1), "How are YOU?", "replaceText(str, from, to)");
+    ed.replaceText("you?", { line: 1, ch: 8 });
+    is(ed.getText(1), "How are you?", "replaceText(str, from)");
+    ed.replaceText("Hello.");
+    is(ed.getText(), "Hello.", "replaceText(str)");
+
+    ed.insertText(", sir/madam", { line: 0, ch: 5});
+    is(ed.getText(), "Hello, sir/madam.", "insertText");
+
+    // Add-ons
+    ed.extend({ whoami: () => "Anton", whereami: () => "Mozilla" });
+    is(ed.whoami(), "Anton", "extend/1");
+    is(ed.whereami(), "Mozilla", "extend/2");
+
+    // Line classes
+    ed.setText("Hello!\nHow are you?");
+    ok(!ed.hasLineClass(0, "test"), "no test line class");
+    ed.addLineClass(0, "test");
+    ok(ed.hasLineClass(0, "test"), "test line class is there");
+    ed.removeLineClass(0, "test");
+    ok(!ed.hasLineClass(0, "test"), "test line class is gone");
+
+    // Font size
+    let size = ed.getFontSize();
+    is("number", typeof size, "we have the default font size");
+    ed.setFontSize(ed.getFontSize() + 1);
+    is(ed.getFontSize(), size + 1, "new font size was set");
+
+    teardown(ed, win);
+  });
+}