objectcache,resourceloader,rdbms,jobqueue: Widen @Covers annotations

Krinkle · Krinkle · commit a0115a7075f4 · 2023-04-10T22:00:17.000Z
Follows-up I4c7d826c7ec654b, I1287f3979aba1bf1.

We lose useful coverage and spend valuable time keeping these accurate
through refactors (or worse, forget to do so). The theoretically "bad"
accidental coverage is almost never actually bad.

Having said that, I'm not removing them wholesale (yet). I've audited
each of these specific files to confirm it is a general test of the
specified subject class, and also kept it limited to those specified
classes. That's imho more than 100% of the benefit for less than 1%
of the cost (more because `@covers` is more valuable than the fragile
and corrosive individual private method tracking in tests that
inevitably get out of date with no local incentive to keep them up to
date).

Cases like structure tests keep `@coversNothing` etc and we still don't
count coverage of other classes. There may be a handful of large
legacy classes where some methods are effectively class-like in
complexity and that's why it's good for PHPUnit to offer the precision
instrument but that doesn't meant we have to use that by-default for
everything.

I think best practice is to write good narrow unit tests, that reflect
how the code should be used in practice. Not to write bad tests and
hide part of its coverage within the same class or even namespace.
Fortunately, that's generally what we do already it's just that we
also kept these annotations still in many cases.

This wastes time to keep methods in sync, time to realize (and fix)
when other people inevitably didn't keep them in sync, time to find
uncovered code only to realize it is already covered, time for a less
experienced engineer to feel obligate to and do write a low quality
test to cover the "missing" branch in an unrealistic way, time wasted
in on-boarding by using such "bad" tests as example for how to use
the code and then having to unlearn it months/years later, loss of
telemetry in knowing what code actually isn't propertly tested due to
being masked by a bad test, and lost oppertunities to find actually
ununused/unreachable code and to think about how to instead structure
the code such that maybe that code can be removed.

------

Especially cases like LBFactoryTest.php were getting out of hand,
and in GlobalIdGeneratorTest.php we even resorted to reminding people
with inline comments to keep tags in sync.

Change-Id: I69b5385868cc6b451e5f2ebec9539694968bf58c
diff --git a/tests/phpunit/integration/includes/libs/uuid/GlobalIdGeneratorTest.php b/tests/phpunit/integration/includes/libs/uuid/GlobalIdGeneratorTest.php
@@ -3,6 +3,9 @@
 use Wikimedia\Timestamp\ConvertibleTimestamp;
 use Wikimedia\UUID\GlobalIdGenerator;
 
+/**
+ * @covers \Wikimedia\UUID\GlobalIdGenerator
+ */
 class GlobalIdGeneratorTest extends PHPUnit\Framework\TestCase {
 
 	use MediaWikiCoversValidator;
@@ -12,13 +15,7 @@ class GlobalIdGeneratorTest extends PHPUnit\Framework\TestCase {
 	private $globalIdGenerator;
 
 	/**
-	 * Test that generated UIDs have the expected properties
-	 *
 	 * @dataProvider provider_testTimestampedUID
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newTimestampedUID88
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getTimestampedID88
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newTimestampedUID128
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getTimestampedID128
 	 */
 	public function testTimestampedUID( $method, $digitlen, $bits, $tbits, $hostbits ) {
 		$id = $this->globalIdGenerator->$method();
@@ -67,22 +64,15 @@ public function testTimestampedUID( $method, $digitlen, $bits, $tbits, $hostbits
 		}
 	}
 
-	/**
-	 * [ method, length, bits, hostbits ]
-	 * NOTE: When adding a new method name here please update the covers tags for the tests!
-	 */
 	public static function provider_testTimestampedUID() {
+		// [ method name, expected length, bits, hostbits ]
 		return [
 			[ 'newTimestampedUID128', 39, 128, 46, 48 ],
 			[ 'newTimestampedUID128', 39, 128, 46, 48 ],
 			[ 'newTimestampedUID88', 27, 88, 46, 32 ],
 		];
 	}
 
-	/**
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newUUIDv1
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getUUIDv1
-	 */
 	public function testUUIDv1() {
 		$ids = [];
 		for ( $i = 0; $i < 100; $i++ ) {
@@ -112,9 +102,6 @@ public function testUUIDv1() {
 		$this->assertEquals( array_unique( $ids ), $ids, "All generated IDs are unique." );
 	}
 
-	/**
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newUUIDv4
-	 */
 	public function testUUIDv4() {
 		$ids = [];
 		for ( $i = 0; $i < 100; $i++ ) {
@@ -130,9 +117,6 @@ public function testUUIDv4() {
 		$this->assertEquals( array_unique( $ids ), $ids, 'All generated IDs are unique.' );
 	}
 
-	/**
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newRawUUIDv4
-	 */
 	public function testRawUUIDv4() {
 		for ( $i = 0; $i < 100; $i++ ) {
 			$id = $this->globalIdGenerator->newRawUUIDv4();
@@ -153,9 +137,6 @@ public function testRawUUIDv4() {
 		}
 	}
 
-	/**
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newSequentialPerNodeID
-	 */
 	public function testNewSequentialID() {
 		$id1 = $this->globalIdGenerator->newSequentialPerNodeID( 'test', 32 );
 		$id2 = $this->globalIdGenerator->newSequentialPerNodeID( 'test', 32 );
@@ -166,10 +147,6 @@ public function testNewSequentialID() {
 		$this->assertGreaterThan( $id1, $id2, "IDs increasing in value" );
 	}
 
-	/**
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::newSequentialPerNodeIDs
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getSequentialPerNodeIDs
-	 */
 	public function testNewSequentialIDs() {
 		$ids = $this->globalIdGenerator->newSequentialPerNodeIDs( 'test', 32, 5 );
 		$lastId = null;
@@ -191,7 +168,6 @@ public static function provideGetTimestampFromUUIDv1() {
 	 * @param string $uuid
 	 * @param string $ts
 	 * @dataProvider provideGetTimestampFromUUIDv1
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getTimestampFromUUIDv1
 	 */
 	public function testGetTimestampFromUUIDv1( string $uuid, string $ts ) {
 		$this->assertEquals( $ts, $this->globalIdGenerator->getTimestampFromUUIDv1( $uuid ) );
@@ -209,7 +185,6 @@ public static function provideGetTimestampFromUUIDv1InvalidUUIDv1() {
 	/**
 	 * @param string $uuid
 	 * @dataProvider provideGetTimestampFromUUIDv1InvalidUUIDv1
-	 * @covers \Wikimedia\UUID\GlobalIdGenerator::getTimestampFromUUIDv1
 	 */
 	public function testGetTimestampFromUUIDv1InvalidUUIDv1( string $uuid ) {
 		$this->expectException( InvalidArgumentException::class );
