Bug: Providing global.config.compilerOptions.whitespace doesn’t work consistently

[ghost]

Describe the bug

During the upgrade process of a project to Vue 3 & Vue Test Utils 2, I’ve noticed a failing test that’s caused by a different whitespace setting used during test execution than what’s otherwise used in the project (via compiler options set in the project’s webpack configuration).

After trying to provide a minimal reproduction, it looks like setting global.config.compilerOptions.whitespace via a mount call’s options doesn’t always work. Specifically, setting it once (to any value) seems to prevent it being set to a different value in subsequent mount calls.

To Reproduce

Run the following test code in a project with @vue/test-utils installed. Both tests should pass, but the second will fail. Note also how changing the order of the tests makes it so that the test will fail that’s now the second even though it previously passed.

const { mount } = require('@vue/test-utils')

const Component = {
  template: `
    <div>
      <h2>
        Heading
      </h2>
    </div>
  `
}

// Skipping this test allows the second test pass. Without skipping it, the second test fails.
test('works with whitespace “preserve”', () => {
  const wrapper = mount(Component, {
    global: {
      config: {
        compilerOptions: {
          whitespace: 'preserve',
        },
      },
    },
  })

  expect(wrapper.html()).toBe(`<div>
  <h2>
    Heading
  </h2>
</div>`)
})

test('works with whitespace “condense”', () => {
  const wrapper = mount(Component, {
    global: {
      config: {
        compilerOptions: {
          whitespace: 'condense',
        },
      },
    },
  })

  expect(wrapper.html()).toBe(`<div>
  <h2> Heading </h2>
</div>`)
})

Used Jest configuration:

module.exports = {
  testEnvironment: 'jsdom',
  transform: {
    '^.+\\.js$': 'babel-jest',
  },
}

Expected behavior

Related information:

• @vue/test-utils version: 2.0.0-rc.21
• Vue version: none
• node version: v16.15.0
• npm (or yarn) version: v8.10.0

Additional context

I’ve tried avoiding this issue by globally setting this in a Jest setup file, but that didn’t help.

import { config } from '@vue/test-utils'

config.global.config.compilerOptions = {
  whitespace: 'preserve',
}

[freakzlike]

I'm not sure, but I think this has been removed by #1408 ?

[cexbrayat]

Yes, exactly. compilerOptions have no effect in the config of VTU.

You need to configure Jest as explained here https://github.com/vuejs/vue-jest#global-jest-options