E2E Tests: Add basic coverage for the Gutenberg plugin

[ockham]

Try to activate and install the Gutenberg plugin. This will catch naming collisions between Core and GB (see Core ticket 57197 for an example).

To test:

1. Check out this branch and run npm run env:start.
2. Run npm run test:e2e -- tests/e2e/specs/gutenberg-plugin.test.js locally and verify that it passes.
3. Add a function definition to Core that's also present in Gutenberg (without function_exists guards or the like). I use the following:

diff --git a/src/wp-settings.php b/src/wp-settings.php
index 3ed93b2f36..d2fdafc74b 100644
--- a/src/wp-settings.php
+++ b/src/wp-settings.php
@@ -8,6 +8,10 @@
  * @package WordPress
  */
 
+function gutenberg_style_engine_get_styles() {
+       die();
+}
+
 /**
  * Stores the location of the WordPress directory of functions, classes, and core content.
  *

4. Run npm run test:e2e -- tests/e2e/specs/gutenberg-plugin.test.js again and watch it fail.

Trac ticket: https://core.trac.wordpress.org/ticket/57197

---

This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[ockham]

As an alternative, we could consider making a WP CLI based test.

Pro:

• Probably runs faster than an e2e test.

Con:

• Doesn't really seem to fit into any of our current test frameworks (neither PHP/JS unit tests nor e2e tests).

[costdev]

Thanks for the PR @ockham!

This review just contains a couple of minor suggestions for consistency with other tests and the Javascript documentation standards.

[fullofcaffeine]

This is great! Do you think it's a better approach than running core tests in Gutenberg PRs (like I originally discussed here: https://wordpress.slack.com/archives/C03B0H5J0/p1650590706137509), or perhaps they're not mutually exclusive? I'd say they are complementary, so we could also try a similar approach in the GB repo.

EDIT: I now see this is not really for running core GB PHPUnit tests in core, but only for activating the plugin, which is also great but not the same thing I was talking about above when I mentioned core tests in GB. Still, this is a great step forward!

[ockham]

This is great! Do you think it's a better approach than running core tests in Gutenberg PRs (like I originally discussed here: https://wordpress.slack.com/archives/C03B0H5J0/p1650590706137509), or perhaps they're not mutually exclusive? I'd say they are complementary, so we could also try a similar approach in the GB repo.

EDIT: I now see this is not really for running core GB PHPUnit tests in core, but only for activating the plugin, which is also great but not the same thing I was talking about above when I mentioned core tests in GB. Still, this is a great step forward!

Thank you! Yeah, so this would be complementary to running Core's tests on Gutenberg PRs. (The latter sounds a bit familiar BTW: WordPress/gutenberg#26418 😬)

[fullofcaffeine]

(The latter sounds a bit familiar BTW: WordPress/gutenberg#26418 grimacing)

Oh gosh! I didn't recall this PR, thanks for pointing that out! We should definitely resume work there!

[costdev]

Thanks for the updates @ockham, LGTM! 👍

[ockham]

Thank you for reviewing @costdev!

Committed to Core in https://core.trac.wordpress.org/changeset/54913/.