The code I'm trying to test relies on RequireJs loader plugins. Example with requirejs/text:
require(['text!templates/foo'], function (data) {
// handle loaded data
});
For a specific unit test, I'm trying to mock the response for text!templates/foo and override with one relevant for the test:
it('should load a template', function (done) {
// TODO: mock 'text!templates/foo' here to return 'mock_data'
// templateViewer uses the text plugin internally to do the actual loading
templateViewer.templateFor('foo', function (error, templateData) {
expect(templateData).toEqual('mock_data');
done();
});
});
I've looked at RequireJs dependency mock solutions, especially Squire.js but it seems they are all suited for mocking regular dependencies and not plugin responses.
I've also looked at stub libraries like sinon to maybe replace the actual require call but that seems problematic.
What's the recommended practice? I prefer not to replace the entire text plugin with a mock one in my requirejs configuration, just override some of its responses in specific tests.
My setup is node+mocha+requirejs
Edit
Please see this example fiddle project to see my issue with Squire:
http://runnable.com/VUBoI0ex6v9Gs-BJ/squirejs-with-plugins-for-node-js-and-hello-world
This will mock what you'd get from requiring text!foo/x.html. Plugins are not special, you just need to mock the entire path, including the plugin name.
var requirejs = require("requirejs");
var assert = require("assert");
requirejs.config({
baseUrl: __dirname,
packages: [
{
name: "squire",
location: "node_modules/squirejs",
main: "src/Squire"
}
]
});
var x;
before(function (done) {
requirejs(["squire"], function (Squire) {
var injector = new Squire();
injector.mock("text!foo/x.html", "foo").require(["text!foo/x.html"],
function (_x) {
x = _x;
done();
});
});
});
it("foo", function () {
assert.equal(x, "foo");
});
The problem you run into with the example code you added to your question is that you use the global require instead of using a require passed by your loader. You should add require as a dependency:
define(['require', ....], function (require, ....) {
The require module is special and reserved by RequireJS. It returns a reference to the require function. You must use it, for instance, when you use RequireJS's contexts so that a module loaded in a specific context uses a require function that is bound to that context. SquireJS also needs you to do this so that it can trap your calls to require. The global require bypasses SquireJS.
Related
I'm writing tests for a JS application using Jasmine and testdouble.js as a mocking library. I am using AMD format to organize code in modules, and RequreJS as a module loader. I was wondering how to use testdouble.js to replace dependency for the module being tested that is in AMD format and it is loading via RequireJS. The documentation is unclear about this or I am missing something, so if someone could point me in the right direction.
I'll post the example bellow that illustrates my setup and the problem that I am facing.
car.js
define("car", ["engine"], function(engine) {
function drive = {
engine.run();
}
return {
drive: drive
}
});
engine.js
define("engine", function() {
function run() {
console.log("Engine running!");
}
return {
run: run
}
});
car.spec.js
define(["car"], function(car) {
describe("Car", function() {
it("should run the motor when driving", function() {
// I am not sure how to mock the engine's object run method
// and where to place that logic, in beforeEach or...
td.replace(engine, "run");
car.drive();
// How to verify that when car.run() has executed, it calls this mocked method
td.verify(engine.run());
});
});
});
testdouble.js does not have any explicit support for AMD modules. The only module-related tricks it offers are Node.js specific and built on top of Node's CJS module loader.
What you would need to do in this case is require from the test a reference to engine and replace the run property, which it seems like you've done (your example is incomplete).
If you do this, don't forget to run td.reset() in an afterEach to restore the original properties to anything you replace!
So I'm trying to set up Typescript and Chutzpah for testing purposes. Typescript is set up to output in this format:
define(['require', 'exports', './someModule'], function(require, exports, someModule) {
//examplecode
});
Which works fine, the problem occurs when someModule is actually a directory with an index.js.
/app
app.js
/someModule
index.js
require.js is unable to resolve someModule in this way and the test fails.
Is there any way to tell require.js that this is a module?
RequireJS won't automatically check for the presence of index.js and load that as your module. You need to tell RequireJS that when you want to load someModule, it should load someModule/index. I'd set a map in my call to require.config:
require.config({
[ ... ]
map: {
'*': {
someModule: 'someModule/index',
}
},
});
You have to adjust the name you give there so that it is a path relative to your baseUrl. It's not clear from the information you give in your question what it should be.
(For the record, there's also a packages setting that you could probably tweak to do what you want but putting something packages says "this is a package", which is not what you appear to have here. So I would not use it for what you are trying to do.)
I didn't like the configuration in map either. The most simple way I accomplished this was writing a plugin for require.
Let's name the plugin mod, where it is to be used as mod!module/someModule, you can also call it index as in index!module/someModule, whatever suits you best.
define(function(require, exports, module) {
// loading module/someModule/index.js with `mod!`
var someModule = require('mod!module/someModule');
// whatever this is about ..
module.exports = { .. };
});
So lets assume you have paths set in require's configuration with some sort of project structure:
- app
- modules
- someModule/index.js // the index we want to load
- someModule/..
- someModule/..
- etc
- plugins
- mod.js // plugin to load a module with index.js
Requires config:
require.config({
paths: {
'module': 'app/modules',
// the plugin we're going to use so
// require knows what mod! stands for
'mod': 'app/plugins/mod.js'
}
});
To read all the aspects of how to write a plugin, read the docs at requirejs.org. The simplest version would be to just rewrite the name of the requested "module" you are attempting to access and pass it back to load.
app/plugins/mod.js
(function() {
define(function () {
function parse(name, req) {
return req.toUrl(name + '/index.js');
}
return {
normalize: function(name, normalize) {
return normalize(name);
},
load:function (name, req, load) {
req([parse(name, req)], function(o) {
load(o);
});
}
};
});
})();
This is not production code, it's just a simple way to demonstrate that requires config wasn't meant to solve problems like this.
Using RequireJS I'm building an app which make extensive use of widgets. For each widget I have at least 3 separate files:
request.js containing code for setting up request/response handlers to request a widget in another part of my application
controller.js containing handling between model and view
view.js containing handling between user and controller
Module definition in request.js:
define(['common/view/widget/entity/term/list/table/controller'],
function(WidgetController) { ... });
Module definition in controller.js:
define(['common/view/widget/entity/term/list/table/view'],
function(WidgetView) { ... });
Module definition of view.js is:
define(['module','require'],function(module,require) {
'use strict';
var WidgetView = <constructor definition>;
return WidgetView;
});
I have lots of these little situations as above in the case of widgets I have developed. What I dislike is using the full path every time when a module is requiring another module and both are located in the same folder. I'd like to simply specify as follows (assuming we have a RequireJS plugin which solves this for us):
define(['currentfolder!controller'],
function(WidgetController) { ... });
For this, I have written a small plugin, as I couldn't find it on the web:
define({
load: function (name, parentRequire, onload, config) {
var path = parentRequire.toUrl('.').substring(config.baseUrl.length) + '/' + name;
parentRequire([path], function (value) {
onload(value);
});
}
});
As you might notice, in its basic form it looks like the example of the RequireJS plugins documentation.
Now in some cases, the above works fine (e.g. from the request.js to the controller.js), but in other cases a load timeout occurs (from controller.js to view.js). When I look at the paths which are generated, all are proper RequireJS paths. Looking at the load timeouts, the following is logged:
Timestamp: 13-09-13 17:27:10
Error: Error: Load timeout for modules: currentfolder!view_unnormalized2,currentfolder!view
http://requirejs.org/docs/errors.html#timeout
Source File: http://localhost/app/vendor/requirejs/require.js?msv15z
Line: 159
The above log was from a test I did with only loading the view.js from controller.js using currentfolder!view in the list of modules in the define statement. Since I only requested currentfolder!view once, I'm confused as to why I both see currentfolder!view_unnormalized2 and currentfolder!view in the message.
Any idea as to why this might be happening?
My answer may not answer your primary questions, but it will help you achieve what you're trying to do with your plugin.
In fact, Require.js support relative paths for requiring modules when using CommonJS style. Like so:
define(function( require, exports, module ) {
var relativeModule = require("./subfolder/module");
module.exports = function() {
console.log( relativeModule );
};
});
I notice in the documentation there is a way to pass custom configuration into a module:
requirejs.config({
baseUrl: './js',
paths: {
jquery: 'libs/jquery-1.9.1',
jqueryui: 'libs/jquery-ui-1.9.2'
},
config: {
'baz': {
color: 'blue'
}
}
});
Which you can then access from the module:
define(['module'], function (module) {
var color = module.config().color; // 'blue'
});
But is there also a way to access the top-level paths configuration, something like this?
define(['module', 'require'], function (module, require) {
console.log( module.paths() ); // no method paths()
console.log( require.paths() ); // no method paths()
});
FYI, this is not for a production site. I'm trying to wire together some odd debug/config code inside a QUnit test page. I want to enumerate which module names have a custom path defined. This question touched on the issue but only lets me query known modules, not enumerate them.
It is available, but it's an implementation detail that shouldn't be depended on in production code ( which you've already said it's not for, but fair warning to others! )
The config for the main context is available at require.s.contexts._.config. Other configurations will also hang off of that contexts property with whatever name you associated with it.
I don't believe require exposes that anywhere, at least I can't find it looking through the immense codebase. There are two ways you could achieve this though. The first and most obvious is to define the config as a global variable. The second, and closer to what you want, is to create a require plugin that overrides the load function to attach the config to the module:
define({
load: function (name, req, onload, config) {
req([name], function (value) {
value.requireConfig = config;
onload(value);
});
}
});
I am currently using requirejs to manage module js/css dependencies.
I'd like to discover the possibilities of having node do this via a centralized config file.
So instead of manually doing something like
define([
'jquery'
'lib/somelib'
'views/someview']
within each module.
I'd have node inject the dependencies ie
require('moduleA').setDeps('jquery','lib/somelib','views/someview')
Anyway, I'm interested in any projects looking at dependency injection for node.
thanks
I've come up with a solution for dependency injection. It's called injectr, and it uses node's vm library and replaces the default functionality of require when including a file.
So in your tests, instead of require('libToTest'), use injectr('libToTest' { 'libToMock' : myMock });. I wanted to make the interface as straightforward as possible, with no need to alter the code being tested. I think it works quite well.
It's just worth noting that injectr files are relative to the working directory, unlike require which is relative to the current file, but that shouldn't matter because it's only used in tests.
I've previously toyed with the idea of providing an alternate require to make a form of dependency injection available in Node.js.
Module code
For example, suppose you have following statements in code.js:
fs = require('fs');
console.log(fs.readFileSync('text.txt', 'utf-8'));
If you run this code with node code.js, then it will print out the contents of text.txt.
Injector code
However, suppose you have a test module that wants to abstract away the file system.
Your test file test.js could then look like this:
var origRequire = global.require;
global.require = dependencyLookup;
require('./code.js');
function dependencyLookup (file) {
switch (file) {
case 'fs': return { readFileSync: function () { return "test contents"; } };
default: return origRequire(file);
}
}
If you now run node test.js, it will print out "test contents", even though it includes code.js.
I've also written a module to accomplish this, it's called rewire. Just use npm install rewire and then:
var rewire = require("rewire"),
myModule = rewire("./path/to/myModule.js"); // exactly like require()
// Your module will now export a special setter and getter for private variables.
myModule.__set__("myPrivateVar", 123);
myModule.__get__("myPrivateVar"); // = 123
// This allows you to mock almost everything within the module e.g. the fs-module.
// Just pass the variable name as first parameter and your mock as second.
myModule.__set__("fs", {
readFile: function (path, encoding, cb) {
cb(null, "Success!");
}
});
myModule.readSomethingFromFileSystem(function (err, data) {
console.log(data); // = Success!
});
I've been inspired by Nathan MacInnes's injectr but used a different approach. I don't use vm to eval the test-module, in fact I use node's own require. This way your module behaves exactly like using require() (except your modifications). Also debugging is fully supported.