Add Health Checks

[bradp]

Proposed changes

Implements a variety of Health Checks to the Site Health page.

Jira tickets: PRESS7-108, PRESS7-109, PRESS7-110, PRESS7-111, PRESS7-118, PRESS7-112, PRESS7-113, PRESS7-121, PRESS7-107, PRESS7-119, PRESS7-120, PRESS7-114, PRESS7-115, PRESS7-116, PRESS7-117.

Type of Change

• New feature (non-breaking change which adds functionality)

Screenshot

Checklist

• I have read the CONTRIBUTING doc
• I have viewed my change in a web-browser
• Linting and tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

This PR adds HealthCheckManager.php which is a helper class to set up and add health checks to the Site Health page. This is used in HealthChecks.php to add the health checks to the Site Health page.

This makes it so adding a new health check is as simple as:

$manager->addHealthCheck( [
  'id'    => 'example-health-check',
  'title' => __( 'Example Health Check', 'newfold-performance-module' ),
  'pass'  => __( 'Example health check passed', 'newfold-performance-module' ),
  'fail'  => __( 'Example health check failed', 'newfold-performance-module' ),
  'text'  => __( 'This is some text to explain the health check to the user.', 'newfold-performance-module' ),
  'test'  => function () {
    // Example test for a constant being defined and having a specific value.
    return ( defined( 'EXAMPLE_CONSTANT' ) && EXAMPLE_CONSTANT === 'example-value' );
  },
] );

This PR also adds Health Checks that are commented out for the following PRs

• Enhance/press7 60 jetpack boost #25
• link prefetch new feature #26
• Image Optimization: Add Lazy Loading Support #32

[arunshenoy99]

Just a few minor things, @bradp. Everything else looks good to me! 😃

[arunshenoy99]

I think this works well for now. But if this file grows into a large monolith in the future, do you think it might make sense to create an abstract class for new health checks to inherit from?

For instance, we could have a HealthChecks directory with an AbstractHealthCheck.php file that defines and documents all the necessary fields. A class like LinkPrefetchHealthCheck.php could then inherit from it and include all tests related to link prefetching.

In this file, we can simply call $manager->addHealthCheck( new LinkPrefetchHealthCheck() );. This approach would provide better validation and typing in PHP, prevent files from becoming too large, group related functionality, and avoid people adding random data directly into the manager. What do you think?

[arunshenoy99]

The Link Prefetch and Jetpack Boost stuff has been merged. I'm working on getting the Image Optimization changes merged as soon as possible after a review! 😃

[circlecube]

@bradp can we get these comments addressed and the conflict resolved? Looks like there's a lint check issue(s) too.

[bradp]

I've refactored this, added unit testing, and gotten everything cleaned up!

[arunshenoy99]

@bradp Just one comment regarding the translations namespace. Everything else looks good to me. I'll approve and merge as soon as you update that namespace everywhere. I'll also get this QA'ed meanwhile. Thanks!