feat: scaffold and register cy.mount command for CT

[lmiller1990]

• Closes https://cypress-io.atlassian.net/browse/UNIFY-1387

note: forked from #20893
note: the generated file will be invalid until https://cypress-io.atlassian.net/browse/UNIFY-1386 lands, which bundles the mount commands in the binary.

User facing changelog

Scaffold correct supportFile for component testing, including adding custom mount command and type definitions, if using TypeScript.

Additional details

We register a convinient cy.mount command for CT when scaffolding a new project, or migrating an existing one.

Example for a project using React and TypeScript:

// ***********************************************************
// This example support/component.ts is processed and
// loaded automatically before your test files.
//
// This is a great place to put global configuration and
// behavior that modifies Cypress.
//
// You can change the location of this file or turn off
// automatically serving support files with the
// 'supportFile' configuration option.
//
// You can read more here:
// https://on.cypress.io/configuration
// ***********************************************************
// Import commands.js using ES2015 syntax:
import './commands'

// Alternatively you can use CommonJS syntax:
// require('./commands')
import { mount } from 'cypress/react'
import type { MountReturn } from 'cypress/react'

// Augment the Cypress namespace to include type definitions for
// your custom command.
// Alternatively, can be defined in cypress/support/component.d.ts
// with a <reference path="./component" /> at the top of your spec.
declare global {
  namespace Cypress {
    interface Chainable {
      mount(...): Cypress.Chainable<MountReturn>
    }
  }
}

Cypress.Commands.add('mount', mount)

// Example use:
// cy.mount(<MyComponent />)

How has the user experience changed?

Better scaffolding for CT based on your framework.

PR Tasks

• Have tests been added/updated?
• Has the original issue (or this PR, if no issue exists) been tagged with a release in ZenHub? (user-facing changes only)
• Has a PR for user-facing changes been opened in cypress-documentation?
• Have API changes been updated in the type definitions?
• Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

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[lmiller1990]

Moved to packages/scaffold-config, trying to consolidate all the scaffolding code in one place.

[cypress]

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Test summary

17812 • 0 • 217 • 0 • 1

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Run details

Project	cypress
Status	Passed
Commit	d304fba
Started	Apr 7, 2022 1:35 AM
Ended	Apr 7, 2022 1:46 AM
Duration	11:49 💡
OS	Linux Debian - 10.10
Browser	Multiple

View run in Cypress Dashboard ➡️

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Flakiness

	cypress/e2e/commands/xhr.cy.js		1
1	... > no status when request isnt forced 404

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[ZachJW34]

Straightforward, works great. Moving the remaining scaffolding logic is 🔥

[tgriesser]

This ... here isn't meant to be what we actually ship, I mostly meant it to indicate that it should be is supposed to be filled in with the appropriate mount signature dependent on the framework chosen

[tgriesser]

I guess it could be as simple as

declare global {
  namespace Cypress {
    interface Chainable {
      mount: typeof mount
    }
  }
}      

[lmiller1990]

🤦‍♂️

[lmiller1990]

Done. d304fba