Add unit and functional test suites

[loevgaard]

Adds a real test setup: a unit and a functional PHPUnit suite, with database-backed functional tests isolated by dama/doctrine-test-bundle (every test runs in a transaction that is rolled back).

Suites

unit (tests/Unit, no database) — Prophecy-based, BDD-style test names:

• DI: Configuration, SetonoSyliusFacebookExtension, OverrideDefaultPixelProviderPass
• Pixel model, PixelContext, DoctrineBasedPixelProvider, AdminMenuListener
• PixelFixture, PixelExampleFactory, PixelType (Symfony TypeTestCase)
• All Conversions API events (ProductViewed, CategoryViewed, ProductAddedToCart, OrderPlaced, CheckoutStarted)
• All event subscribers, including the error-swallowing behaviour of EventSubscriber::track()

functional (tests/Functional, boots the test application) — a small FunctionalTestCase creates the channel/admin user/pixels it needs inside the transaction:

• PixelRepository::findEnabledByChannel()
• The setono_facebook_pixel fixture end-to-end
• Admin CRUD through the Symfony test client: list, create, validation error, update, delete, unauthenticated redirect

Test application

• DAMADoctrineTestBundle registered for test/test_cached, PHPUnit extension in phpunit.xml.dist
• config/packages/test/{assets,webpack_encore}.yaml: functional tests do not need a frontend build (verified with public/build removed, i.e. CI conditions)
• config/bootstrap.php: require_once the Composer autoloader with a sane path. The previous require dirname(__DIR__) . '../../../vendor/autoload.php' redeclared the autoloader under Infection, so every mutant died with a fatal error — the mutation job could never have produced a real result.

src/ — small behaviour-preserving simplifications to make branches testable

• getTaxonName() in the product events: getMainTaxon() ?? getTaxons()->first()
• FormatAmountTrait: amounts are integer cents, so $amount / 100 is exact and needs no round()
• ViewCategorySubscriber: LimitIterator instead of a counter + break

Mutation testing

Infection now runs at 100% MSI (157 mutants killed, 0 escaped, 0 uncovered). Equivalent mutants are ignored explicitly in infection.json.dist: CastString on the defensive (string) casts of nullable getters in Event\* / the pixel provider, MethodCallRemoval for the type-narrowing Asserts that follow OptionsResolver/DQL validation, and ProtectedVisibility on FormatAmountTrait::formatAmount() (kept protected for subclasses of OrderBasedEvent).

CI

Unit job runs --testsuite unit; integration job runs --testsuite functional after creating the schema; coverage and mutation jobs now start MySQL and create the schema so the functional suite is included.

Dependencies (dev)

dama/doctrine-test-bundle ^7.3 (v8 requires PHPUnit ≥ 10, the plugin pack pins 9.6), symfony/browser-kit, symfony/css-selector.

Verified locally on PHP 8.3: 81 tests green, ECS, PHPStan (level max), Rector, Infection 100%.

https://claude.ai/code/session_013jh2QjzkxAJABPDYB1UiPS

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (eef0385) to head (a777f5e).

Additional details and impacted files

@@              Coverage Diff               @@
##               3.x       #87        +/-   ##
==============================================
+ Coverage     0.00%   100.00%   +100.00%     
+ Complexity     113       110         -3     
==============================================
  Files           25        25                
  Lines          419       400        -19     
==============================================
+ Hits             0       400       +400     
+ Misses         419         0       -419     

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