diff -r 000000000000 -r 6474c204b198 browser/devtools/shadereditor/test/browser_se_editors-lazy-init.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/devtools/shadereditor/test/browser_se_editors-lazy-init.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,48 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests if source editors are lazily initialized.
+ */
+
+function ifWebGLSupported() {
+  let [target, debuggee, panel] = yield initShaderEditor(SIMPLE_CANVAS_URL);
+  let { gFront, ShadersEditorsView } = panel.panelWin;
+
+  try {
+    yield ShadersEditorsView._getEditor("vs");
+    ok(false, "The promise for a vertex shader editor should be rejected.");
+  } catch (e) {
+    ok(true, "The vertex shader editors wasn't initialized.");
+  }
+
+  try {
+    yield ShadersEditorsView._getEditor("fs");
+    ok(false, "The promise for a fragment shader editor should be rejected.");
+  } catch (e) {
+    ok(true, "The fragment shader editors wasn't initialized.");
+  }
+
+  reload(target);
+  yield once(gFront, "program-linked");
+
+  let vsEditor = yield ShadersEditorsView._getEditor("vs");
+  let fsEditor = yield ShadersEditorsView._getEditor("fs");
+
+  ok(vsEditor, "A vertex shader editor was initialized.");
+  ok(fsEditor, "A fragment shader editor was initialized.");
+
+  isnot(vsEditor, fsEditor,
+    "The vertex shader editor is distinct from the fragment shader editor.");
+
+  let vsEditor2 = yield ShadersEditorsView._getEditor("vs");
+  let fsEditor2 = yield ShadersEditorsView._getEditor("fs");
+
+  is(vsEditor, vsEditor2,
+    "The vertex shader editor instances are cached.");
+  is(fsEditor, fsEditor2,
+    "The fragment shader editor instances are cached.");
+
+  yield teardown(panel);
+  finish();
+}