Write tests for CDN mappings

test/test-main.js

-var main = require("./main");
-
-exports["test main"] = function(assert) {
-  assert.pass("Unit test running!");
-};
-
-exports["test main async"] = function(assert, done) {
-  assert.pass("async Unit test running!");
-  done();
-};
-
-require("sdk/test").run(exports);