Skip to content

Commit

Permalink
Merge pull request #3 from simplabs/docs
Browse files Browse the repository at this point in the history
docs
  • Loading branch information
marcoow committed Mar 1, 2016
2 parents b2e61e4 + 2173ca1 commit 0716cce
Show file tree
Hide file tree
Showing 2 changed files with 94 additions and 16 deletions.
108 changes: 93 additions & 15 deletions README.md
Original file line number Diff line number Diff line change
@@ -1,26 +1,104 @@
# Ember-test-selectors
[![Build Status](https://travis-ci.org/simplabs/ember-test-selectors.svg?branch=master)](https://travis-ci.org/simplabs/ember-test-selectors)

This README outlines the details of collaborating on this Ember addon.
# ember-test-selectors

This Ember CLI Addon __removes all HTML 5 data attributes starting with
`data-test-` in all environments other than `development` and `test`__. That
allows using data attributes as selectors for integration and acceptance tests
without polluting the generated markup of the production (or staging etc.)
application.

## Installation

* `git clone` this repository
* `npm install`
* `bower install`
```bash
ember install ember-test-selectors
```

## Why use `data` attributes as test selectors?

Integration and acceptance tests usually __interact with and assert on the
presence of certain elements__ in the markup that an application renders. These
elements are identified using CSS selectors. Most projects use one of three
approaches for CSS selectors in tests:

### Selectors based on HTML structure

This approach simply selects elements by their position in the rendered HTML.
For the following template:

```html
<article>
<h1>Post Title</h1>
<p>Post Body…</p<>
</article>
```

one might select the post's title with the selector `article h1`. Of course
this breaks when changing the `<h1>` to a `<h2>` while the functionality being
tested is probably not affected by that change.

### Selectors based on CSS classes

This approach selects elements by CSS classes. For the following template:

```hbs
<article>
<h1 class="post-title">{{post.title}}</h1>
<p>{{post.body}}</p>
</article>
```

one might select the post title with the selector `.post-title`. This of course
breaks when the CSS class is changed or renamed, although that would only be a
visual change which shouldn't affect the tests at all.

Many projects use special CSS classes that are only used for testing to
overcome this problem like `js-post-title`. While that approach is definitely
more stable it is often hard to maintain. Also it is very hard to encode
additional information in these CSS classes like e.g. the post's id.

### Selectors based on `data` attributes

This approach uses HTML 5 `data` attributes to select elements. For the
following template:

```hbs
<article>
<h1 data-test-selector="post-title">{{post.title}}</h1>
<p>{{post.body}}</p>
</article>
```

## Running
one would select the post's title with the selector
`*[data-test-selector="post-title"]`. While the selector is arguably a bit
longer this approach clearly separates the test selectors from the rest of the
markup and is resilient to change as it would simply be applied to the element
rendering the post's title, regardless of the HTML structure, CSS classes etc.
Also it allows to encode more data in the markup like e.g. the post's id:

* `ember server`
* Visit your app at http://localhost:4200.
```hbs
<article>
<h1 data-test-selector="post-title" data-test-resource-id="{{post.id}}">{{post.title}}</h1>
<p>{{post.body}}</p>
</article>
```

## Running Tests
`ember-test-selectors` makes sure to remove all these `data` attributes in all
environments except `development` and `test` so that __users will have
perfectly clean HTML delivered__:

* `npm test` (Runs `ember try:testall` to test your addon against multiple Ember versions)
* `ember test`
* `ember test --server`
```html
<article>
<h1>My great post</h1>
<p>Bla bla…</p>
</article>
```

## Building
## License

* `ember build`
ember-test-selectors is developed by and &copy;
[simplabs GmbH](http://simplabs.com) and contributors. It is released under the
[MIT License](https://github.com/simplabs/ember-simple-auth/blob/master/LICENSE).

For more information on using ember-cli, visit [http://www.ember-cli.com/](http://www.ember-cli.com/).
ember-test-selectors is not an official part of [Ember.js](http://emberjs.com)
and is not maintained by the Ember.js Core Team.
2 changes: 1 addition & 1 deletion index.js
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ module.exports = {
name: 'test-selectors',

included: function() {
if (this.app.environment === 'production') {
if (this.app.environment !== 'development' && this.app.environment !== 'test') {
this.app.registry.add('htmlbars-ast-plugin', {
name: 'strip-test-selectors',
plugin: StringTestSelectorsTransform
Expand Down

0 comments on commit 0716cce

Please sign in to comment.