Enzyme: Render Testing dangerouslySetInnerHTML containing an xlink

[peter-mouland]

I have recently rewrote a test (from v2 to v3) and found now that xlink is removed from the dangerouslySetInnerHTML ...

I'm not convinced this is really enzyme removing this, but it does seem to render correctly in the browser.

Have i found an issue, or am I missing something?

Thanks for your time.

I found this while recoding for the issue https://github.com/airbnb/enzyme/issues/1297 in order to separate the 2

Example component:

// svg.js
import React from 'react'

export default ({ height, width, children, className, symbol = false, id, use, ...props }) => {
  const isBase64 = typeof children === 'string' && children.indexOf('data') === 0
  let svg = use ? `<svg ><use xlink:href='#${use}' /></svg>` : children
  if (id) svg = svg.replace(/(<svg[^>]*) id=".*?"/ig, '$1').replace('<svg', `<svg id="${id}"`)
  if (height) svg = svg.replace(/(<svg[^>]*) height=".*?"/ig, '$1').replace('<svg', `<svg height="${height}"`)
  if (width) svg = svg.replace(/(<svg[^>]*) width=".*?"/ig, '$1').replace('<svg', `<svg width="${width}"`)
  if (symbol) svg = svg.replace('<svg', '<svg style="display: none;" ><symbol')
  return isBase64
    ? <img src={svg} className={className} {...props} />
    : <span dangerouslySetInnerHTML={{ __html: svg }} className={className} {...props} />
}

Failing Test

// svg.spec.js


import React from 'react'
import { shallow, render } from 'enzyme'
import Chance from 'chance'

import Svg from './Svg'

const chance = new Chance()
const svg = '<svg class="test-svg" xmlns="http://www.w3.org/2000/svg" />'
const defaultMockProps = {
  id: chance.word()
}

describe('Svg', () => {
  it('renders the use href using xlink (needed for safari)', () => {
    const component = render(<Svg use={defaultMockProps.id} />)
    expect(component.html()).toContain(`xlink:href="#${defaultMockProps.id}"`)
  })

Result:

    Expected string:
      "<svg><use href=\"#ku\"/></svg>"
    To contain value:
      "xlink:href=\"#ku\""

React:

<svg><use xlink:href="#my-test"></use></svg>

---

This test works using shallow:

  it('renders the use href using xlink (needed for safari)', () => {
    const component = shallow(<Svg use={defaultMockProps.id} />)
    expect(component.html()).toContain(`xlink:href='#${defaultMockProps.id}'`)
  })

[ljharb]

It seems like the kind of nonstandard property that React itself is removing. What version of react?

[peter-mouland]

This was with my upgrade from React 15 (tested w/ enzyme v2) to React 16 (tested w/ enzyme v3)

[ljharb]

@peter-mouland by upgrading both react and enzyme at once, it's pretty hard to know where the problem is. Could you get enzyme 3 with react 15 passing first, and then upgrade to React 16?

[peter-mouland]

sure, that's fair - i'm in the UK though so not right now ;)
hopefully get a chance to do it tomorrow or Friday (depending on work!), but shouldn't take long just to change the adapter. will let you know

[peter-mouland]

I can confirm:

tests

  it('renders the use href using xlink (needed for safari) original', () => {
    const component = render(<Svg use={defaultMockProps.id} />)
    const use = component.find('use')
    expect(use.prop('xlink:href')).toBe(`#${defaultMockProps.id}`)
  })

  it('renders the use href using xlink (needed for safari) w/ render', () => {
    const component = render(<Svg use={defaultMockProps.id} />)
    expect(component.html()).toContain(`xlink:href="#${defaultMockProps.id}"`)
  })

  it('renders the use href using xlink (needed for safari) w/ shallow', () => {
    const component = shallow(<Svg use={defaultMockProps.id} />)
    expect(component.html()).toContain(`xlink:href="#${defaultMockProps.id}"`)
  })

result: enzyme 2 and React 15.6.2

// original
*pass*

// w/render   
*pass*

// w/shallow
*pass*

result: enzyme 3 React 15 (same result with React 16)

// original
    Expected value to be (using ===):
      "#wugjaco"
    Received:
      undefined

// w/render   
    Expected string:
      "<svg><use href=\"#wugjaco\"/></svg>"
    To contain value:
      "xlink:href=\"#wugjaco\""

// w/shallow
*pass*

_(original fails as find('use').prop('xlink:href') returns length 0)_

[ljharb]

Thanks! That means it's not specific to the react 16 adapter, which means it's a v3 issue.

@aweary, could you take a look into this one?

[chenesan]

Hi @ljharb I'd like to look into this. I may try to fix issues about selectors recently.

[chenesan]

Provide a simpler test case:

it('render `xlink:href` in html of dangerouslySetInnerHTML', () => {
      const xlinkId = 'TEST';
      const svg = `<svg><use xlink:href="#${xlinkId}" /></svg>`;
      const wrapper = render(<span dangerouslySetInnerHTML={{ __html: svg }} />);

      expect(wrapper.html()).contain(`xlink:href="#${xlinkId}"`);
    });

It looks like it's an issue in cheerio side. cheerio converts xlink:href attribute to href after 1.0.0.
In enzyme v2 we used cheerio@^0.22.0 so the above test will pass.

See cheeriojs/cheerio#1101 .

[ljharb]

In that case, closing in favor of #1297 which already is tracking that cheerio issue.