Linting Rule: no-enzyme-when-hooks

[billfienberg]

Issue Description

As a developer that is trying to test a hook-based function component, I want to see a linting error in my editor when I try to use Enzyme, so I learn to not use that pattern ASAP.

Background

Until React@16.8, most components were written using class components. Additionally, most components were tested with Enzyme.

Once React@16.8 was released, people started using function components with hooks.

Problem

People run into problems when trying to test hook-based function components with Enzyme because Enzyme doesn't fully support hooks.

Actual example of VFS team member encountering this problem:

• https://dsva.slack.com/archives/C5HP4GN3F/p1588100133239100

Front end tasks

1. Write the linting rule
2. Install the linting rule
3. Configure the linting rule

Acceptance Criteria

Developers see a linting error in their console when they try to test a hook-based function component using Enzyme.

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[mchelen-gov]

another place to start might be adding a warning about this (and possible workarounds) to https://department-of-veterans-affairs.github.io/veteran-facing-services-tools/getting-started/common-tasks/new-unit-test

[erikphansen]

The issue isn't with Enzyme, it's with shallow mounting. Folks could still use Enzyme's mount and it will work with hooks.

[mchelen-gov]

@erikphansen yup true, maybe we could mention that in docs?