RPP / Add 100% unit test coverage requirement for src

[RadoslavGeorgiev]

Changes proposed in this Pull Request

Allow the src directory's unit coverage to be checked separately from includes.

1. There is a new test:php-coverage-src npm command, which only checks src, and is significantly faster than the full npm run test:php-coverage command.
2. A new "Code coverage (src) / Code coverage" workflow in GitHub which fails if coverage is less than 100%.

How this was achieved:

• Introduced a custom phpunit-src.xml.dist to allow the selection of only the src directory. Otherwise it is the same as phpunit.xml.dist.
• bin/phpunit.sh does not run by with -c phpunit.xml.dist by default anymore, instead allowing other commands to define it.
• Introduced 3 new files:
  1. bin/check-src-test-coverage.sh for the local command. Identical to bin/check-test-coverage.sh, but with the new XML config.
  2. bin/run-ci-tests-check-src-coverage.bash for the CI job, almost identical to the non-src one as well.
  3. .github/workflows/src-coverage.yml is the definition of the GitHub workflow.

Testing instructions

1. Run both npm run test:php-coverage and npm run test:php-coverage-src locally to make sure they work.
2. All CI checks should pass in GitHub.

---

• Run npm run changelog to add a changelog file, choose patch to leave it empty if the change is not significant. You can add multiple changelog files in one PR by running this command a few times.
• Covered with tests (or have a good reason not to test in description ☝️)

[htdat]

Left some comments for re-using current bash and workflow files (i.e. DRY principle), rather than introducing new files with very similar structures of existing files - which can be a burden for Harmony to update them in the future.

[RadoslavGeorgiev]

@htdat all good points. I've removed all nearly duplicate files, except for the XMLs. Could you please take another look?

[htdat]

@RadoslavGeorgiev - Looks excellent now.

I've removed all nearly duplicate files, except for the XMLs.

Agreed, we need to have a new XML config file to have a separate code coverage report for src except that if there is a way that I don't know. However, even if there was a way, it seemed it's more complicated than just changing a few config lines.

---

My last comment is that we might also need to use the phpunit.xml.dist config for only includes, and leave src for phpunit-src.xml.dist.

This is my suggestion:

Index: phpunit.xml.dist
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
--- a/phpunit.xml.dist	(revision e5dc5a913730827dfdf40671d0e2788cd528ba02)
+++ b/phpunit.xml.dist	(date 1698307623999)
@@ -11,6 +11,7 @@
 		<testsuite name="WCPay">
 			<directory suffix=".php">./tests/unit</directory>
 			<exclude>./tests/unit/multi-currency</exclude>
+			<exclude>./tests/unit/src</exclude>
 		</testsuite>
 		<testsuite name="WCPayMultiCurrency">
 			<directory suffix=".php">./tests/unit/helpers</directory>
@@ -22,12 +23,6 @@
 	<filter>
 		<whitelist>
 			<directory suffix=".php">includes</directory>
-			<directory suffix=".php">src</directory>
-			<exclude>
-				<!-- Service providers are simple, and ideally should not be used within tests. -->
-				<directory suffix=".php">src/Internal/DependencyManagement/ServiceProvider</directory>
-			</exclude>
 		</whitelist>
 	</filter>
-
 </phpunit>

[RadoslavGeorgiev]

@htdat I'd prefer to intentionally keep src covered by the standard commands. Most developers are/will not be aware of the difference in src requirements at first, and it might be confusing for them. I wanted a separate set of rules and commands:

• To allow quick src checks locally, especially for coverage.
• Enforce a 100% coverage in GitHub
• Not to run tests separately.

[htdat]

@RadoslavGeorgiev - that also makes sense. If so, at least, we would still get rid of directory src from the code coverage in phpunit.xml.dist to maintain really 60% for includes. Otherwise, includes can go lower 60% while src keeps 100%, but the overall coverage can be still 60% - which is definitely NOT what we'd like to have at the end.

[RadoslavGeorgiev]

@htdat done with 3 total files:

• npm run test:php through phpunit.xml.dist is the standard unit tests for all of the plugin, as devs are used to.
• npm run test:php-coverage through phpunit-includes.xml.dist, also used for CI checks.
• npm run test:php-coverage-src through phpunit-src.xml.dist, also used for CI checks.

The includes check is now down about 1% because of excluding src.

[htdat]

I think that makes sense now. Thanks for addressing my review.

[RadoslavGeorgiev]

Merging without Harmony's approval for now. If needed, we can change things.