Summary

• Added Jest test environment for unit and integration tests
• Added Playwright test environment for e2e tests
• Removed previous unit and integration test environments (mocha + chai + jsdom)
• Removed previous e2e test environment (Cypress.io)
• Ported existing unit, integration, and e2e tests of value to new environments

Details

An implementation of Jest+Playwright. This setup offers a number of advantages over the existing test structures (mocha+chai+jsdom & Cypress):

• Ability to perform unit, integration, and e2e tests with one test configuration.
• Separate test environments for unit + integration (Jest+jsdom) and e2e (Jest + Playwright) tests.
• Testing in real browsers (Chromium, Firefox, and Webkit) for e2e tests.
• Significantly faster and easier to create complex tests that require custom docsify configurations and site content thanks to a newdocsifyInit() helper. This abstraction allows new docsify instances to be dynamically generated declaratively with a fraction of the code that would otherwise be required. It also removes the need to manage a large collection of fixture files (although you can use them if you prefer).
• Documentation content is mapped to/docs/ on the local testing server, making it easy to use our documentation as fixtures without having to duplicate the content.
• The local./lib/ directory is also mapped to/lib/ on the local testing server, making it easy to use the latest docsify JS and CSS.
• Example tests provided to help reduce the learning curve for new contributors

Changes have been made to the GitHub workflows to accommodate these changes:

• A new "Build & Test" workflow has been added. This workflow runs all tests in a single workflow to prevent separate checkout+build operations for each test type. It updates the test matrix to build and test docsify on Linux (ubuntu-latest), macOS (macos-latest), and Windows (windows-latest) on the three latest LTS versions of Node (10, 12, 14).
• The linting workflow has been updated to prevent building docsify, as there is no need to perform a build to link source code (the build output is ignored by eslint).

Part of the motivation for doing this work was to allow me to create proper tests for#1271. The other part was to try and clean up our test configuration so that we can offer a reliable and easy-to-learn environment for devs to work in. I looked at our existing test structures and realized there was no way for me do what I needed to do easily without creating complex tests with repeated boilerplate code and a large number of fixtures. Specifically, testing#1271 requires multiple docsify configurations that must be run in a browser with and without additional third-party scripts (vue.js). With this setup, every custom docisfy test is between 8 and 11 lines of code and zero test-specific file fixtures.

A few tips for reviewers:

1. All Jest and Playwright code is isolated in a new./test/ directory. This means this PR can safely be merged and it will not affect existing tests.
2. Start by reviewing/test/README.md. This file provides an overview of the test environments, global variables, and CLI commands available.
3. Review./jest.config.js and note that we are using Jestprojects to simplify unique environment configurations for unit, integration, and e2e tests.
4. Review./test/helpers/docsify-init.js. This helper greatly simplifies the process of creating dynamic docsify sites for individual tests.
5. For Jest (and jsdom) testing, review/test/unit/example.test.js and/test/integration/example.test.js.
6. For Jest + Playwright testing, review/test/e2e/example.test.js.
7. I've created real-world tests for vue.js reactivity (the reasonFix Vue Reactivity #1271 exists). These are available for review in/test/e2e/vue.test.js;
8. VSCode debug configurations have been added to make testings a single test or file easier. You can access these by clicking the debug icon on VSCode's sidebar (or pressing SHFT+CMD/CTRL+D). The two tests currently in place are:
   • Run current test file
   • Run selected test name (requires highlightingdescribe() ortest() name)
   • Update current test file snapshot(s)
   • Update selected test name snapshot(s) (requires highlightingdescribe() ortest() name)

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
• Other, please describe: Automated Testing

Does this PR introduce a breaking change? (check one)

• Yes
• No

The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's title (e.g.fix #xxx[,#xxx], where "xxx" is the issue number)

Fix#1217

You have tested in the following browsers: (Providing a detailed version will be better.)

• Chrome
• Firefox
• Safari
• Edge
• IE

If adding anew feature, the PR's description includes:

• A convincing reason for adding this feature
• Related documents have been updated
• Related tests have been updated