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Stephan Hagemann

Showing and hiding conditional HTML without Javascript

Stephan Hagemann
Tuesday, May 21, 2013

Have you ever filled out an address form that had a checkbox for “my shipping address differs from my mailing address”? When you click that box a conditional form part gets revealed that allows you to enter another address. We had to build something very similar the other day and stumbled on a neat way to make the conditional part show and hide with CSS only.
Continue reading →

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Ken Mayer

Sencha Touch BDD – Part 5 – Controller Testing

Ken Mayer
Saturday, May 18, 2013

Sencha Touch BDD

tl;dr

A multi-part series of articles on how to test Sencha Touch applications. It uses Jasmine for unit testing and Siesta for integration testing.

Part 5 – Controller Testing

Recap

Part 4 Introduced PhantomJS as an easy and faster alternative to headful Jasmine testing. Part 3 added jasmine-ajax so we can verify that stores and models react properly to back-end data. We also learned how to use stores to test views, without depending on a back-end server. In Part 2 I showed you how to unit test Sencha model classes in Jasmine. In Part 1 I showed you how to set up your Sencha Touch development environment to use the Jasmine JavaScript test framework.

It’s a control thing, but I will let you understand

Sencha Touch controllers usually live within the context of a single application object. Normally, this is handled for you when you invoke Ext.Application() in your app.js file. It creates a singleton object for you in the namespace of your application. For example, if you configured your application’s name to be ‘SenchaBdd’, then the application will be available as the .app attribute of the global SenchaBdd object, that is, SenchaBdd.app.

Unit testing should not have a running application, however. The point is that we are testing classes in isolation. There’s nothing isolated about an integrated, running, Javascript application. There is a relatively simple solution, however; You need to create you own “test” application object that you can then pass as a configuration option when you create controllers under test.

$ cat spec/javascripts/controller/MyControllerSpec.js
describe('SenchaBdd.controller.MyController', function() {
    var controller, app;
    beforeEach(function () {
        app = Ext.create('Ext.app.Application', {name: 'SenchaBdd'});
        controller = Ext.create('SenchaBdd.controller.MyController', { application: app });
        controller.launch();
    });

    afterEach(function() { app.destroy(); })

You may want to refactor the application creation and tear-down into a spec helper, to DRY out your tests.

Test behaviors, not events

It’s tempting to write a Jasmine test that tries to trigger an event in the DOM, then follow the event handling through the application. This is the road to hell. If you find yourself trying to simulate an event, please stop. That is what integration tests are better at doing. Controllers are classes like any other, and you should test methods in the same way. For example, let’s drive out a behavior where, when a user taps on the ‘Buy’ button our application sends a request to the back-end.

describe('SenchaBdd.controller.MyController', function () {
  var controller, app;
  beforeEach(function () {
    app = Ext.create('Ext.app.Application', {name: 'SenchaBdd'});
    controller = Ext.create('SenchaBdd.controller.MyController', { application: app });
    controller.launch();
  });

  afterEach(function () {
    app.destroy();
  });

  it('#newOrder', function () {
    var order = controller.newOrder();
    expect(order.$className).toEqual('SenchaBdd.model.MyModel');
    expect(order.phantom).toBeTruthy();
  });

  describe('#onBuy', function() {
    it('calls save on the order', function() {
      var myOrder = Ext.create('SenchaBdd.model.MyModel');
      spyOn(myOrder, 'save');
      spyOn(controller, 'newOrder').andCallFake(function() {
        return myOrder;
      });
      
      controller.onBuy()
      
      expect(myOrder.save).toHaveBeenCalled();
    })
  })
});

You might notice that I neither ‘tap’, nor do I test for a ‘POST’ ajax call. The former is better tested through integration tests. The latter is better tested in the model. All the controller need do assert that the model was saved. We trust external classes to function (because they’re tested, too, right?) Testing the #save method on the model follows the same process as testing stores, as I outlined in Part3. Another thing to note is that, under test, this controller does not have any views associated with it; Ext.ComponentQuery calls will return empty (undefined) results. This is to be expected in an isolated test, but may make for some head scratching when you first encounter it. If you must test something in the DOM, you should be writing an integration test anyway.

Ext.define('SenchaBdd.controller.MyController', {
  extend:   'Ext.app.Controller',
  config:   {
    views:   ['MyView'],
    refs:    {
      buyButton: 'myview #buyButton'
    },
    control: {
      buyButton: { tap: 'onBuy' }
    }
  },
  newOrder: function () {
    return Ext.create('SenchaBdd.model.MyModel');
  },
  onBuy:    function () {
    this.newOrder().save();
  }
});

As a personal preference, and make it easier to test and refactor, I have a #newOrder method that delegates to the model to create a new instance.

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Ken Mayer

Sencha Touch BDD – Part 4 – PhantomJS

Ken Mayer
Friday, May 10, 2013

Sencha Touch BDD

tl;dr

A multi-part series of articles on how to test Sencha Touch applications. It uses Jasmine for unit testing and Siesta for integration testing.

Part 4 – Headless testing using PhantomJS

Part 3 added jasmine-ajax so we can verify that stores and models react properly to back-end data. We also learned how to use stores to test views, without depending on a back-end server. In Part 2 I showed you how to unit test Sencha model classes in Jasmine. In Part 1 I showed you how to set up your Sencha Touch development environment to use the Jasmine JavaScript test framework.

I hear it’s all about the cloud these days

Not only do we use Test Driven Development, we test all the time (see also TATFT). In fact, continuous testing is a key component in a well-run agile practice. Pivotal developed ciborg (previously known as Lobot), to automatically deploy Jenkins servers in the cloud. Jasmine has a continuous integration target in its rake tasks, rake jasmine:ci. If you’ve never run it before, now is a good time to try it. You’ll notice that Jasmine launches an instance of the Firefox browser, runs the test suite, then reports the results. That’s great if you’ve got (1) Firefox and (2) a machine that has a display! When you run your CI tests in the cloud, the virtual machines may not be configured with a virtual display. Furthermore, the process is terribly slow.

In this installment, we’ll see how to mix in PhantomJS so we can run our Jasmine tests without the need for a visual browser. PhantomJS is orders of magnitude faster, too.

Do the install dance

  1. Add ‘jasmine-phantom’ to your Gemfile
index e6b5daf..612fb25 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,4 @@ source "https://rubygems.org"
 
 gem "rake"
 gem "jasmine"
+gem "jasmine-phantom"

and modify your Rakefile to load the PhantomJS tasks:

--- a/Rakefile
+++ b/Rakefile
@@ -2,6 +2,7 @@
 begin
   require 'jasmine'
   load 'jasmine/tasks/jasmine.rake'
+  load 'jasmine-phantom/tasks.rake'
 rescue LoadError
   task :jasmine do

Finally, run bundle install

Now, when you run rake -T from the command line, you’ll see a new target:

$ rake -T jasmine
rake jasmine             # Run specs via server
rake jasmine:ci          # Run continuous integration tests
rake jasmine:phantom:ci  # Run jasmine specs using phantomjs and report the results

Run rake

Running it will the phantom:ci target will start the Jasmine continuous integration tests in PhantomJS instead of Firefox.

$ rake jasmine:phantom:ci 2>1 /dev/null
[2013-05-06 20:28:15] INFO  WEBrick 1.3.1
[2013-05-06 20:28:15] INFO  ruby 1.9.3 (2012-11-10) [x86_64-darwin12.2.0]
[2013-05-06 20:28:15] INFO  WEBrick::HTTPServer#start: pid=17061 port=60080
Waiting for jasmine server on 60080...

8 specs | 0 failing
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Ken Mayer

Sencha Touch BDD – Part 3 – Testing Views and Mocking Stores

Ken Mayer
Sunday, May 5, 2013

Sencha Touch BDD

tl;dr

A multi-part series of articles on how to test Sencha Touch applications. It uses Jasmine for unit testing and Siesta for integration testing.

Part 3 – Testing Views and Mocking Stores

In Part 1 I showed you how to set up your Sencha Touch development environment to use the Jasmine JavaScript test framework. In Part 2 I showed you to unit test Sencha model classes in Jasmine.

I don’t normally test views, but when I do

There’s an old MVC mantra: “Fat models, skinny controllers and stupid views.” We don’t want complex logic in our views; that makes them hard to maintain. We don’t want any business logic in our controllers, either. That’s why we have models. Views should be so simple that they don’t require tests. There is a gray area with Sencha, however, where we found testing to be useful in our design process. It has to do with how views interact with stores.

Stores are essentially collections of models. They also encapsulate the persistence layer logic, separate from the business logic of the model. DataViews are a special class of Views in Sencha Touch that will consume a collection to generate a list-type view via a template.

Here are two goals for testing views and stores:

  • Does the view consume the right fields from the store, without hitting the back-end for data?
  • Does the store organize the data from the back-end, i.e. create the interface that is used by the view? Again, without hitting the back-end for data.

Small steps and iterate

Let’s define a very simple view via tests, we’ll make it work using an in-line store, then we’ll refactor the store into its own class. Next, we’ll refactor the storage class to use a remote back-end.

Ext.require('SenchaBdd.view.MyView');

describe('SenchaBdd.view.MyView', function () {
  it("has a list of colors", function () {
    var view = Ext.create('SenchaBdd.view.MyView', {
      renderTo: 'jasmine_content',
      store:    {
        fields: ['color'],
        data:   [
          {color: 'red'},
          {color: 'green'},
          {color: 'blue'}
        ]
      }
    });

    expect(Ext.DomQuery.select('.favorite-color').map(function (el) {
      return el.textContent
    }).join(', ')).toEqual('red, green, blue');

  });
});

Sencha does not come bundled with jQuery, so if you were expecting a DOM query like, $(“.favorite-color”), you might be surprised by the expectation. Ext has its own flavor of querying the DOM, using Ext.DomQuery.select.

Try implementing the view on your own to make the test pass. It should look remarkably similar to this:

Ext.define('SenchaBdd.view.MyView', {
  extend: 'Ext.dataview.DataView',
  xtype:  'myview',
  config: {
    itemTpl: '<div class="favorite-color">{color}</div>'
  }
});

In your application, you probably won’t hardwire a store into the view. In fact, you will probably embed this little view inside a larger container, like so (this adds another tab to the sample app):

--- a/app/view/Main.js
+++ b/app/view/Main.js
@@ -10,6 +10,11 @@ Ext.define('SenchaBdd.view.Main', {
 
         items: [
+            {
+              title: 'Favorites',
+              iconCls: 'star',
+              xtype: 'myview',
+              store: 'mystore',
+              styleHtmlContent: true
+            },
             {
                 title: 'Welcome',
                 iconCls: 'home',

Let’s create a store so our view will show us something:

Ext.define('SenchaBdd.store.MyStore', {
  extend: 'Ext.data.Store',
  config:    {
    storeId: 'mystore',
    fields: ['color'],
    data:   [
      {color: 'red'},
      {color: 'green'},
      {color: 'blue'}
    ]
  }
});

In order to see this view, we’ll need to add it to our app.js file:

--- a/app.js
+++ b/app.js
@@ -31,7 +31,11 @@ Ext.application({
     ],
 
     views: [
-        'Main'
+        'Main', 'MyView'
     ],

+    stores: [
+            'MyStore'
+    ],
 
     icon: {

Now, let’s go back and refactor our test so it uses MyStore instead of one that was hard-wired.

--- a/spec/javascripts/view/MyViewSpec.js
+++ b/spec/javascripts/view/MyViewSpec.js
@@ -2,17 +2,16 @@ Ext.require('SenchaBdd.view.MyView');
 
 describe('SenchaBdd.view.MyView', function () {
   it("has a list of colors", function () {
+    var store = Ext.create('SenchaBdd.store.MyStore', {
+      data:     [
+        {color: 'red'},
+        {color: 'green'},
+        {color: 'blue'}
+      ]
+    });
     var view = Ext.create('SenchaBdd.view.MyView', {
       renderTo: 'jasmine_content',
-      store:    {
-        fields: ['color'],
-        data:   [
-          {color: 'red'},
-          {color: 'green'},
-          {color: 'blue'}
-        ]
-      }
-
+      store:    store
     });
     expect(Ext.DomQuery.select('.favorite-color').map(function (el) {
       return el.textContent

All of our tests should remain green, but we’ve removed the “fake” store from our test.

Let’s get dynamic

Static data stores are boring. The fun starts when you start talking to a back-end API. Let’s say that we have a server that responds to an end point of ‘/colors.json’ with a list of favorite colors. We can even “fake” it by placing a file in the appropriate place. Even so, we don’t want our tests to make network calls to the back-end. That’s not appropriate for unit testing. We’ll use Jasmine’s AJAX mocking helper, jasmine-ajax. At the time of this writing, the 2.0 branch had not been merged into the main line, and we need the 2.0 branch in order to work with Ext.

cd spec/javascripts/helpers
curl -O 'https://raw.github.com/pivotal/jasmine-ajax/2_0/lib/mock-ajax.js'
git add ./mock-ajax.js

And we’ll create our first store spec in spec/javascripts/store/MyStoreSpec.js:

describe('SenchaBdd.store.MyStore', function () {
  var store;
  beforeEach(function () {
    jasmine.Ajax.useMock();
    clearAjaxRequests();
    store = Ext.create('SenchaBdd.store.MyStore')
  });

  it('calls out to the proper url', function () {
    store.load();
    var request = mostRecentAjaxRequest();
    expect(request.url).toEqual('/colors.json');
  });
});

Notice that I call jasmine.Ajax.useMock() and clearAjaxRequests() in the set up block. This is because I want to wait until the very last moment to turn on ajax mocking. The Ext class loader might still be trying to load a class (via xhr), and the mocker will prevent that from happening. I also clear all previous requests (in case there were any left over, to prevent test polution).

When you run Jasmine, you’ll get a test failure, “TypeError: Cannot read property ‘url’ of null” because we haven’t set up the proxy in the store, yet. Let’s do that.

$ cat app/store/MyStore.js
Ext.define('SenchaBdd.store.MyStore', {
  extend: 'Ext.data.Store',
  config: {
    autoLoad: true,
    storeId:  'mystore',
    fields:   ['color'],
    proxy:    {
      type:       'ajax',
      url:        '/colors.json'
    }
  }
});

Now, when you run the test suite, you’ll get a different error! This is because the default settings for the ajax proxy enables caching, paging, etc. Things we don’t need, so we have to turn them off:

    proxy:   {
      type:       'ajax',
      url:        '/colors.json',
      noCache:    false,
      pageParam:  false,
      startParam: false,
      limitParam: false
    }

Now our api test is green! You can even test this in the application by dropping a file, ‘colors.json’ into the public directory.

Let’s add one more test to finish things off.

  it('populates the collection', function () {
    store.load();
    var mockedRequest = mostRecentAjaxRequest();

    mockedRequest.response({
      status:       200,
      responseText: [
        {color: 'red'},
        {color: 'green'},
        {color: 'blue'}
      ]
    });

    expect(store.getCount()).toEqual(3);
    expect(store.getAt(0).get('color')).toEqual('red');
    expect(store.getAt(1).get('color')).toEqual('green');
    expect(store.getAt(2).get('color')).toEqual('blue');
  });

Every mocked ajax request has a response() method that you can use to inject your own response, synchronously, to your tests. This confirms that MyStore properly parses and arranges the received data so that it can be presented by the view.

Validate your mocks

We now have 2 tests that depend on a back-end to respond in a specified way. How do we keep these tests from drifting out of sync? Since we’ve mocked the store in our view test, we might never know if the back-end API changes!

You can wrap Jasmine expectation in functions so that they are reusable. Then we can mix this matcher into our view test to confirm that the store we use there is the same.

Let’s add this function to our SpecHelper.js file:

function myStoreDataIsValid(store) {
  expect(store.getCount()).toEqual(3);
  expect(store.getAt(0).get('color')).toEqual('red');
  expect(store.getAt(1).get('color')).toEqual('green');
  expect(store.getAt(2).get('color')).toEqual('blue');
}

And we’ll replace our existing tests with a single line:

  myStoreDataIsValid(store);

We’ll also modify the MyViewSpec.js:

--- a/spec/javascripts/view/MyViewSpec.js
+++ b/spec/javascripts/view/MyViewSpec.js
@@ -9,6 +9,7 @@ describe('SenchaBdd.view.MyView', function () {
         {color: 'blue'}
       ]
     });
+    myStoreDataIsValid(store);
     var view = Ext.create('SenchaBdd.view.MyView', {
       renderTo: 'jasmine_content',
       store:    store

Similarly, we can refactor our colors array into var:

--- a/spec/javascripts/helpers/SpecHelper.js
+++ b/spec/javascripts/helpers/SpecHelper.js
@@ -16,6 +16,15 @@ afterEach(function () {
     domEl.setAttribute('style', 'display:none;');
 });
 
+var colorsJSON;
+beforeEach(function() {
+  colorsJSON = [
+    {color: 'red'},
+    {color: 'green'},
+    {color: 'blue'}
+  ];
+});

And then use colorsJSON in our tests.

--- a/spec/javascripts/store/MyStoreSpec.js
+++ b/spec/javascripts/store/MyStoreSpec.js
@@ -18,11 +18,7 @@ describe('SenchaBdd.store.MyStore', function () {
 
     request.response({
       status:       200,
-      responseText: [
-        {color: 'red'},
-        {color: 'green'},
-        {color: 'blue'}
-      ]
+      responseText: colorsJSON
     });
     myStoreDataIsValid(store);
   });

and

--- a/spec/javascripts/view/MyViewSpec.js
+++ b/spec/javascripts/view/MyViewSpec.js
@@ -3,12 +3,9 @@ Ext.require('SenchaBdd.view.MyView');
 describe('SenchaBdd.view.MyView', function () {
   it("has a list of colors", function () {
     var store = Ext.create('SenchaBdd.store.MyStore', {
-      data:     [
-        {color: 'red'},
-        {color: 'green'},
-        {color: 'blue'}
-      ]
+      data:     colorsJSON
     });
+    myStoreDataIsValid(store);
     var view = Ext.create('SenchaBdd.view.MyView', {
       renderTo: 'jasmine_content',
       store:    store

What we’ve managed, so far

The toy app is coming along. We’ve test driven a DataView that consumes a back-end API. We’ve added the mock-ajax library so we can unit tests our stores in isolation. We’ve even seen a few techniques for keeping our mocks from getting out of sync (although, if you’ve been paying attention, I’ve still left a gaping hole, that needs to be plugged).

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Ken Mayer

Sencha Touch BDD Part 2

Ken Mayer
Friday, April 26, 2013

Sencha Touch BDD

tl;dr

A multi-part series of articles on how to test Sencha Touch applications. It uses Jasmine for unit testing and Siesta for integration testing.

Part 2 – Unit Testing Models

In Part 1 I showed you how to set up your Sencha Touch development environment to use the Jasmine JavaScript test framework. We’re going to take a bit of a breather from all the hard work we did last week. In this blog, I’m going to show you how to test simple models.

Let’s have some fun, shall we?

Test-Driven-Development starts with a test, of course. Let’s write one that just asserts that our model class exists:

$ cat spec/javascripts/model/MyModelSpec.js
describe('SenchaBdd.model.MyModel', function() {
  it('exists', function() {
    var model = Ext.create('SenchaBdd.model.MyModel');
    expect(model.$className).toEqual('SenchaBdd.model.MyModel');
  });
});

When we run our tests in the browser, Jasmine reports this:

  Error: [Ext.Loader] Failed loading synchronously via XHR: 'app/model/MyModel.js'; 
  please verify that the file exists. XHR status code: 404

Which is just Ext’s very formal way of saying, “No such class exists” because we haven’t written it, yet.

Let’s write one that makes the test pass:

$ cat app/model/MyModel.js
Ext.define('SenchaBdd.model.MyModel', {
  extend: 'Ext.data.Model'
});

We have proven that we can create a new class, and that it’s name is what we expect.

Attributes

Let’s assert that our model has some attributes:

$ cat spec/javascripts/model/MyModelSpec.js
it('has data', function () {
  var model = Ext.create('SenchaBdd.model.MyModel', {
    name: 'Test',
    email: 'test@example.com',
    favoriteColor: 'blue'
  });
  expect(model.get('name')).toEqual('Test');
  expect(model.get('email')).toEqual('test@example.com');
  expect(model.get('favoriteColor')).toEqual('blue');
});

Which of course, fails, until we add some fields to our model:

$ cat app/model/MyModel.js
Ext.define('SenchaBdd.model.MyModel', {
  extend: 'Ext.data.Model',
  config: {
    fields: [
      { name: 'name', type: 'string' },
      { name: 'email', type: 'string' },
      { name: 'favoriteColor' }
    ]
  }
});

Default values

Let’s say that our model has some default values

$ cat spec/javascripts/model/MyModelSpec.js
it('has default values', function() {
  var model = Ext.create('SenchaBdd.model.MyModel')
  expect(model.get('favoriteColor')).toEqual('yellow');
})

Reload the Jasmine runner in the browser and …

  SenchaBdd.model.MyModel has default values.
  Expected undefined to equal 'yellow'.

Which is easily resolved by adding it to the class:

$ cat app/model/MyModel.js
{ name: 'favoriteColor', defaultValue: 'yellow' }

Validations

One last simple piece, let’s assert that email is a required field.

$ cat spec/javascripts/model/MyModelSpec.js
it('requires an email address', function() {
  var model = Ext.create('SenchaBdd.model.MyModel');
  var errors = model.validate();
  expect(errors.isValid()).toBeFalsy();

  expect(errors.getByField('email')[0].getMessage()).toEqual('must be present');
})

The first expectation asserts that the model is not valid at all. It’s a gatekeeper test. The second test asserts that there’s validation error on the email field (and not some other field).

$ cat app/model/MyModel.js
  config: {
    ...
    validations: [
      { field: 'email', type: 'presence' }
    ]

Roundup

This is a pretty simple set of tests. If you are at all familiar with unit testing, you won’t find much new here. Testing for validations by inspecting on the Errors collection was a little tricky to suss out. Hopefully I’ve saved you a few frustrating moments digging through the source code. What’s also interesting, I think, is how the test report reads:

  SenchaBdd.model.MyModel
    exists
    has data
    has default values
    requires an email address

The test itself communicates something to the reader about the intention of the model. That’s a key concept to understand about TDD; the most important and expensive reader of the application is not the browser, it’s the person who reads and maintains it. It might be your successor or your team mate, or perhaps, yourself, six months from now, when you’ve forgotten everything about this particular patch of code.

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Ken Mayer

Sencha Touch BDD Part 1

Ken Mayer
Wednesday, April 17, 2013

Sencha Touch BDD

tl;dr

A multi-part series of articles on how to test Sencha Touch applications. It uses Jasmine for unit testing and Siesta for integration testing.

Part 1 – Getting Started

In this article you will learn how to set up an application to Jasmine tests in your

Opinionated is a good thing

In my not-so-humble professional opinion, every modern web framework should provide a testing infrastructure with each newly generated application. I’m not concerned if it isn’t my preferred testing package. As long as there’s something. Testing is not an option, and the framework authors probably (hopefully?) test, so why not offer a serving suggestion for new projects? The worst that can happen is that you, the developer, disagree with the choice of framework. There’s a little extra bootstrap cost to replace one framework with another. That’s far less expensive than every new developer discovering a way to test.

Sencha Touch 2.1 has a generator built into its sencha command line tool, but it does not create a test structure as part of the template. This article is the first in a series of discoveries about how to test Sencha Touch applications. I am not claiming that this is the one true way to test. This is not necessarily the best way, either. It is, however, something that works. It installs easily on my development laptop. It gets you to your first passing test quickly. It saves you the cost of exploring all of the options and making these discoveries for yourself. You have plenty of other things to worry about.

But first, you need a web server

Once you’ve installed Sencha Touch and Sencha Command (3.1.0.256 when I wrote this), and you’ve generated the template application, you’ll need to serve the pages locally. Most projects will have some sort of app server already running, but it’s not strictly necessary for testing. When I need to serve pages on my own, I prefer pow. It is a zero-configuration server that can host as many applications as you please. I also like the powder ruby gem; it adds a nice command line interface to manage pow. If you are worried about adding a ruby dependency to your project, stop worrying. Sencha Touch uses the compass ruby gem to generate css files; so you already have a ruby dependency.

pow looks for a rack app, but in my sample app, I don’t have one. pow also looks for a directory named public from which it will server static files. The simplest thing that works is to create a symlink named public that points to the root directory of the project.

# Generate a new ST app
$ cd <touch toolkit directory>
$ sencha generate app senchaBdd ~/workspace/sencha-bdd

# Set up pow/powder
$ cd ~/workspace/sencha-bdd
$ ln -s . public
$ powder up
$ powder link

# Test the server
$ open http://sencha-bdd.dev

If all goes well, you should be able to open the application in any web browser at http://sencha-bdd.dev

Running sample app

Running sample app

Install Jasmine

Installing the stand-alone version of Jasmine will work, but it doesn’t scale to hundreds or thousands of specs. That’s why the Jasmine gem was created. I did some more research and found a way to test using the Jasmine gem.

  1. In the root directory of your project add rake and jasmine to your Gemfile
    $ cat Gemfile
    source "https://rubygems.org"
    
    group :development do
    	gem 'rake'
    	gem 'jasmine'
    end
  2. Run bundle install

  3. Run jasmine init

  4. Jasmine will install a basic set up, but there’s some cruft that you won’t need for a Sencha application.
    rm public/javascripts/Player.js
    rm public/javascripts/Song.js
    rm spec/javascripts/PlayerSpec.js
  5. Edit the src_files entry in spec/javascripts/support/jasmine.yml:
    src_files:
        - touch/sencha-touch-all-debug.js   # Load Sencha library
        - spec/app.js                   # Load our spec Ext.Application
        - app/**/*.js                   # Load source files
  6. Create this file in spec/app.js:
    Ext.Loader.setConfig({
        enabled: true,                  // Turn on Ext.Loader
        disableCaching: false           // Turn OFF cache BUSTING
    });
    
    Ext.Loader.setPath({
        'SenchaBdd': 'app'              // Set the path for all SenchaBdd.* classes
    });
    
    Ext.application({
        name: 'SenchaBdd'               // Create (but don't launch) an application
    });
  7. And this one in spec/javascripts/helpers/SpecHelper.js:
    
    Ext.require('Ext.data.Model');
    
    afterEach(function () {
        Ext.data.Model.cache = {};      // Clear any cached models
    });
    
    var domEl;
    beforeEach(function () {            // Reset the div with a new one.
        domEl = document.createElement('div');
        domEl.setAttribute('id', 'jasmine_content');
        var oldEl = document.getElementById('jasmine_content');
        oldEl.parentNode.replaceChild(domEl, oldEl);
    });
    
    afterEach(function () {             // Make the test runner look pretty
        domEl.setAttribute('style', 'display:none;');
    });

So, what’s going on here? Sencha Touch applications need Ext.Loader to manage class loading. You also need an Ext.Application, especially for controller tests. The modifications to jasmine.yml set up the proper load order, and the jasmine gem will find all of the source files underneath the app/ directory. The app.js is a customized version of your normal app.js that sets up the class loader and global namespace configuration. You should replace “SenchaBdd” with the real name of your application. Two things are happening in SpecHelper.js: First, by default Ext.data.Model caches every model created by the application in a global in-memory array. If you don’t clear it between tests, you can be surprised by test pollution. The second part is to set up and clear a space in the test runner for inserting DOM elements, usually for some sort of view testing.

Create a directory structure that matches your application’s

Your application’s directory structure should look something like this:

├── app
│   ├── controller
│   ├── model
│   ├── profile
│   ├── store
│   └── view

Modify the spec directory so that it mirrors the app/ directory:

├── spec
│   ├── app.js
│   └── javascripts
│       ├── model
│       ├── controller
│       ├── view
│       ├── store
│       ├── profile

Install Jasmine

You can get the stand alone version from http://github.com/pivotal/jasmine. Install it at the in the spec directory. I include the version number, so I can experiment with different versions, but that’s a matter of taste.

├── app
│   ├── controller
│   ├── model
│   ├── profile
│   ├── store
│   └── view
├── public -> .
├── resources/
├── spec/
│   ├── controller
│   ├── jasmine-1.3.1
│   ├── model
│   ├── profile
│   ├── store
│   └── view
└── touch

In order to get Jasmine going, you need a special html file named, by convention, SpecRunner. Add it to spec/ as well. It looks like this:

You will need to modify lines 18 and 22 with the name of your ST app (which can be found in app.json and app.js).

Write one passing test

Create a file, spec/javascripts/sanitySpec.js

describe("Sanity", function() {
  it("succeeds", function() {
    expect(true).toEqual(true);
  });
});


Now load the spec runner into a browser. In the case of this sample app, the url is http://sencha-bdd.dev/spec/SpecRunner.html

Now start the Jasmine spec server from the command line:

    bundle exec rake jasmine

And then open a browser window on http://localhost:8888

You should see the test results with one passing spec.

1 Passing Jasmine Spec

1 Passing Jasmine Spec

If you don’t see this, open up the browser’s developer console to look for clues.

Until next time

That’s it! You now have a complete JavaScript testing framework installed in your application. This is a good time to commit your changes. Celebrate in the glory of the green goodness. You’ve earned it.

Next time, I’ll show you how to test a model class.

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Robbie Clutton

Introducing ElementalJS and the Behaviour Pattern

Robbie Clutton
Thursday, January 17, 2013

We’ll come to ElementalJS a little later but first I wanted to describe the problem it’s trying to solve.

The problem with current Javascript design patterns

There seems to be two mainstream ways of building Javascript applications: DOM event listeners with callback spaghetti or full blown object oriented MVC architecture.

The listeners and callbacks pattern works well for small applications where the entire file fits on your screen. After that it can be difficult to track down where the handlers are for certain events. It can be even more difficult when trying to debug in a browser console when you’re trying to find the handler for that interaction in question.

Object oriented Javascript has been gaining ground but with so many options of which framework to choose from it can feel like an application is putting it’s eggs in one basket by using one of those frameworks. Each has it’s own pro and con list, but sometimes you just need a little bit of whiz bang without managing an application within an application.

There are other tools to help like CommonJS and Asynchronous Module Definitions (AMD) but they don’t answer how to structure an applications Javascript code.

An alternative

An alternative, spaghetti-leaning pattern has emerged on several projects here in the New York office. The pattern has been dubbed ‘data presents’ or ‘behaviours’, depending on the project. This pattern couples a function to an element in the DOM by adding a data attribute to the element itself. This is not having Javascript in a href attribute within an anchor or onchange attribute of a select element, but it does highlight which functions are related to any given element.

This approach tries to embrace the simplicity of binding listeners to DOM events but tries to organise it in such a way to make it scalable and maintainable as the client side code grows.

Here instead of the script looking and binding to events across the whole DOM, an element is passed to a function where it can work on a local scale. There will still be listeners, but with the scope of the parent element the functions will be more tightly focused.

By adding a behaviour through the markup, this means that when looking at some HTML, you can see the behaviours that have been loaded for a particular element and it’s children. This can be useful when attempting to find a callback from a DOM action as typically there will be behaviours wrapped around the HTML.

Typically behaviours are small, focused functions. They are just javascript so can create objects, call functions and trigger or listen to events. Given they are small, this makes them easy to test. We use Jasmine heavily on our projects at Pivotal when testing Javascript, and these small functions are breakfast for Jasmine.

In a Rails project, or something which supports an asset pipeline, these behaviours are best suited to single files per behaviour. Naming a file the same as the behaviour name also increases discoverability in a codebase. For example, the Foo.Bar behaviour is located in foo/bar.js.

Spaghetti code perhaps, but sort of like finding a message within your alphabetti spaghetti.

Alphabetti Spaghetti
With thanks to James Armstrong

What about unobtrusive javascript?

There are four components of unobtrusive javascript:

  • Usability
  • Graceful degradation
  • Accessibility
  • Separation

While three of the four components don’t really affect this pattern as they are in the domain of the application itself, separation of concern between the presentation layer and the Javascript, does.

The section on separation of concerns on Wikipedia covers this concern well. This pattern is quite clearly encouraging the use of putting behaviour into the presentation which is shown to reduce maintainability. So what’s different this time around?

Using this pattern we are not expressively stating what events to fire upon (e.g. onclick or onchange), we are just defining a behaviour that wraps this element. One of the concerns addressed in the separation of concerns section in the Wikipedia article is ease of development but by defining small behaviours they can be easily separated into their own files, have more of a single responsibility and therefore should be easier to test.
What about unobtrusive HTML?

Many Javascript applications will be loaded when the DOM has finished loading and will generally search the entire DOM for elements to attach events to. Using this pattern the element gets passed into the function that contains the behaviour. This enables that function to search the DOM locally and reduce the chance of any changes to the DOM affecting the applications javascript as changes can be localised.

When can I start using ElementalJS?

You can use this right now by using ElementalJS. You can either download the source, or if you’re using Rails theres a handy gem which wraps the file and puts it straight into your asset pipeline. Check out more over at the ElementalJS repository.

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Georg Apitz

How to render jade templates on the server

Georg Apitz
Thursday, January 10, 2013

The best way for Google and friends to crawl and index a page is by finding static content. With applications that make heavy use of libraries like Backbone, Sproutcore or ember.js a lot of the content can be rendered in the browser. This can constitute a serious problem since the support methods from Google et. al. for alternative crawling coem with no guarantees.

We recently ran into this problem and came up with a neet solution where the client side templates can also be rendered server side.

There are two parts to the implementation. First, a method that can take a jade partial and its local variables, compile and evaluate it. Second, a view that calls out to that method and provides the template and the necessary local variables.

Part 1, the application_helper.rb


require 'tilt-jade/jade_js'

module ApplicationHelper
  def html_from_jade_template(partial, options={})
    data = File.open(\
            Rails.root.join("app", "assets", "templates", "#{partial}.js.jst.jade"\
            ))
    compiled = JadeJs.compile(data, locals: {}, client: true, compileDebug: false)

    raw(JadeJs::Source.context.eval("(#{compiled})(#{options[:locals].to_json}, \
        jade.runtime.attrs, jade.runtime.escape, jade.runtime.rethrow, \
        jade.runtime.merge)" \
        ))
  end
end

The method is pretty straight forward, it loads the template from the assets/template directory, compiles it and then evals it with the provided locals. The output is raw html that can be included in your view.

Part 2, a view that requests the compiled and eval’d templates from the server


- body = "This content comes from the server. Remove the param from the url or toggle \
          with the link in the upper right."
#menu
  = html_from_jade_template("home/menu", locals: {items: [{title: "Server"}, \
    {title: "Side"}, {title: "Rendered"}]})
#content
  = html_from_jade_template("home/content", locals: {body: body })

Here the main thing is the call to the method in application helper that will produce the raw html given a template name and the necessary local variables.

That is pretty much it. It may take a little bit to figure out the requirements for the local variables in your template, especially since jade is very strict about them. If it can’t find one it will not compile.

I’ve put an example app on github with the complete source code for this post.

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Robbie Clutton

Using Jasmine on tddium

Robbie Clutton
Tuesday, November 27, 2012

With thanks to Ben we discovered a nice way to get Jasmine tests to work on Tddium today. We had a number of issues with the jasmine-headless-webkit dependency Tddium said we had to use. Issues around requiring a file that required erb to compile; not finding the source files; getting to work in the browser but not the command line and maybe a few others.

Ben pointed out some undocumented configuration for Tddium which outlined ‘custom’ build steps wherein you could call the jasmine:ci rake task. This cleared everything up. Although I’m not sure how as Tddium said it could only cope with a headless browser environment.

Here’s the gist I hope it saves you as much time as it did me.

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Charles Hansen

Hunting Memory Leaks in Backbone

Charles Hansen
Tuesday, October 23, 2012

Ever notice your backbone app slows down considerably after using it for a few minutes? Or maybe your event callbacks are called more than once each time the event fires? Or my favorite, Chrome runs out of memory if you have a few tabs open that have run your entire Jasmine suite? This means you have backbone leaks.

I just spent the last week hunting these down in a very large app. It turns out the problem is tractable with a few guidelines. None of this is ground-breaking, but I wanted to put it all in one place.

1) The object retaining tree in the Chrome heap profiler is amazing. Use it.

2) Restrict use of views in closures, or as contexts to callbacks in event bindings. This is explained in much more detail here. I’ve also personally found nothing but trouble with _.bind for similar reasons.

More specifically, never use model.bind or model.on in a view without keeping track of that binding and remembering to unbind it when you want to tear down the view. This is the motivation for coccyx

3) ParentViews with childViews need to keep track of their children. When you tear down the parent view, you also tear down the child views. Before implementing this step, the object retaining tree for my zombie views was shockingly large. Afterwards, it was a manageable ~4 retainers for the zombies.

Parents keeping track of their children seems simple enough, but it is easy to lose track of the little devils.

For example:

ParentView = Backbone.View.extend({
    render: {
        //render the rest of the view first

        this.collection.each(function(model){
            var childView = new ChildView({model: model});
            this.$("ul").append(childView.render().$el);
        });
    }
});

loses any reference to the child views, and they will almost certainly leak (assuming the child views bind events to their models that need to be cleaned up).

Using the principles names from coccyx, the same code needed to be rewritten as

ParentView = Backbone.View.extend({
    render: {
        //render the rest of the view first

        this.tearDownRegisteredSubviews();

        this.collection.each(function(model){
            var childView = new ChildView({model: model});
            this.$("ul").append(liView.render().$el);

            this.registerSubView(childView);

        });
    }
});

where tearDownRegisteredSubviews calls tearDown on any registered subviews. This way, the only child views still in memory are those initialized in the most recent call to render. Those remaining views should be torn down when the parent is torn down.

View.tearDown itself can be a bit sticky because you still have to worry about event bindings from global objects and other difficult-to-clean sources, but those solutions are more project-specific.

Hope that points you in the right direction.

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