mithril-query
=============
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Query mithril virtual dom for testing purposes

## Installation

    npm install mithril-query --save-dev

## Setup

In order to run tests in mithril 2.x we need to do some setup. That is to mock the dom for the mithril render and request modules.
This can be done by requiring a 'setup' file in your 'mocha' tests with the following contents.

```js
global.window = Object.assign(
  require('mithril/test-utils/domMock.js')(),
  require('mithril/test-utils/pushStateMock')()
)
global.requestAnimationFrame = callback =>
  global.setTimeout(callback, 1000 / 60)
```

## Changes from version 3.x to 4.x

#### Root state access

... is gone, since `mithril` does not provide a way to access it

#### Booleans

... are now rendered as empty strings, like mithril does, because, well, mithril renders

#### Lifecycles

... are now fully supported, including synthetic DOM elements 🎉

#### find/first

... are now returning DOM elements instead of vdom nodes.

#### Custom events

... aren't supported anymore. Feel free to file a ticket, if you want them back.

## Usage

You can run this tests server side or use browserify and run them in browsers.

```js
const m = require('mithril')

module.exports = {
  view: function() {
    return m('div', [
      m('span', 'spanContent'),
      m('#fooId', 'fooContent'),
      m('.barClass', 'barContent'),
    ])
  },
}
```

```js
/* eslint-env mocha */
global.window = Object.assign(
  require('mithril/test-utils/domMock.js')(),
  require('mithril/test-utils/pushStateMock')()
)
global.requestAnimationFrame = callback =>
  global.setTimeout(callback, 1000 / 60)

const simpleModule = require('./simple')
const mq = require('../')

describe('simple module', function() {
  it('should generate appropriate output', function() {
    var output = mq(simpleModule)
    output.should.have('span')
    output.should.have('div > span')
    output.should.have('#fooId')
    output.should.have('.barClass')
    output.should.have(':contains(barContent)')
    output.should.contain('barContent')
  })
})
```

Run the test with

    mocha simple.test.js

## API


### Initialise

First call `mithril-query` with either a vnode or a component. You can call it
with one extra argument which will be used as `attrs` in the component case.

```js
var mq = require('mithril-query')

// plain vnode
var out = mq(m('div'))

// object component
var myComponent = {
  view: function ({ attrs }) {
    return m('div', attrs.text)
  }
}
var out = mq(myComponent, { text: 'huhu' })

// closure component
function myComponent() {
  return {
    view: function ({ attrs }) {
      return m('div', attrs.text)
    }
  }
}
var out = mq(myComponent, { text: 'huhu' })
```

### Query API

As you can see `mq` returns an `out`-Object which has the following test-API.

* `out.first(selector)` – Returns the first element that matches the selector (think `document.querySelector`).
* `out.find(selector)` – Returns all elements that match the selector (think `document.querySelectorAll`).
* `out.has(selector)` –  Returns `true` if any element in tree matches the selector, otherwise `false`.
* `out.contains(string)` – Returns `true` if any element in tree contains the string, otherwise `false`.
* `out.log(selector, [logFN])` – Small helper function to log out what was selected. Mainly for debugging
purposes. You can give an optional function which is called with the result.
It defaults to HTML-Pretty-Printer ([pretty-html-log](https://www.npmjs.com/package/pretty-html-log)] that logs the HTML-representation to `stdout`.

You can use these nice assertions. They throw errors if they're not fulfilled.
See the example in the example folder.

* `out.should.have([count], selector)`

Throws if no element is found with selector. If `count` is given, it throws if
count does not match.

* `out.should.not.have(selector)` – Throws if an element is found with selector.
* `out.should.have.at.least(count, selector)` – Throws if there a fewer than `count` elements matching the selector
* `out.should.have([selector0, selector1, selector2])` – Throws there aren't at least one element for each selector.
* `out.should.contain(string)` – Throws if no element contains `string`.
* `out.should.not.contain(string)` - Throws if any element contains `string`.

### Event triggering

It is also possible to trigger element events like `onfocus` and `onclick` and set values on `<input>`-fields. This allows you to write "integration tests" that run also on server side.

Attention: Currently there is no event bubbling supported.

* `out.click(selector, [eventData])` – Runs `onclick` for first element that matches selector. Optional `eventData` is given
as to the event constructor. `eventData.redraw = false` is respected.
* `out.setValue(selector, string, [eventData])` – Runs `oninput` and `onchange` for first element that matches selector.
* `out.trigger(selector, eventname, [eventData])` – General purpose event triggerer. Calls `eventname` on first matching element.

It also supports key events

* `out.keydown(selector, keycode, [eventData])` – calls `onkeydown` with `keycode`
* `out.keydown(selector, keyname, [eventData])` – calls `onkeydown` with keycode mapped from name. Mapping is done with [this lib](https://github.com/npmcomponent/yields-keycode).

`keyup`, `keypress` are supported as well.

### Auto "Redrawing"

Since `mithril-query` uses `mithril` on a fake DOM, auto rendering works as expected.

Example:

```js
  // module code
  const component = {
    visible: true
    oninit({ state }) {
      state.toggleMe = () => (state.visible = !state.visible)
    },
    view({ state }) {
      return m(
        state.visible ? '.visible' : '.hidden',
        { onclick: state.toggleMe},
        'Test'
      )
    },
  }


  // actual test
  out = mq(component)
  out.should.have('.visible')
  out.click('.visible')
  out.should.not.have('.visible')
  out.should.have('.hidden')
  out.click('.hidden', { redraw: false })
  out.should.have('.hidden')
```

As you can see, you can prevent auto redraw by providing a `redraw: false` as last
argument to `click` method.

You can also manually trigger redraw:

```javascript
var out = mq(module)
out.should.have('.visible')
out.redraw()
```

### helpers

If you need to access the rendered root element you can simply access it with

```javascript
out.rootEl
```

### `onremove` handling

To trigger `onremove`-handlers of all initialized components, just call `out.onremove()`