Merge "tests: Prefer PHPUnit's assertSame() when comparing empty strings"

diff --combined tests/phpunit/includes/db/LBFactoryTest.php
index 033b3f9,f4ddca2..f00499f
--- 1/tests/phpunit/includes/db/LBFactoryTest.php
--- 2/tests/phpunit/includes/db/LBFactoryTest.php
+++ b/tests/phpunit/includes/db/LBFactoryTest.php
@@@ -187,7 -187,7 +187,7 @@@ class LBFactoryTest extends MediaWikiTe
                };
  
                $factory = $this->newLBFactoryMultiLBs();
 -              $this->assertEquals( 0, $countLBsFunc( $factory ) );
 +              $this->assertSame( 0, $countLBsFunc( $factory ) );
                $dbw = $factory->getMainLB()->getConnection( DB_MASTER );
                $this->assertEquals( 1, $countLBsFunc( $factory ) );
                // Test that LoadBalancer instances made during pre-commit callbacks in do not
@@@ -208,7 -208,7 +208,7 @@@
  
                $called = 0;
                $factory = $this->newLBFactoryMultiLBs();
 -              $this->assertEquals( 0, $countLBsFunc( $factory ) );
 +              $this->assertSame( 0, $countLBsFunc( $factory ) );
                $dbw = $factory->getMainLB()->getConnection( DB_MASTER );
                $this->assertEquals( 1, $countLBsFunc( $factory ) );
                // Test that LoadBalancer instances made during pre-commit callbacks in do not
@@@ -475,17 -475,16 +475,16 @@@
                /** @var IMaintainableDatabase $db */
                $db = $lb->getConnection( DB_MASTER, [], '' );
  
-               $this->assertEquals(
+               $this->assertSame(
                        '',
                        $db->getDomainId(),
                        'Null domain ID handle used'
                );
-               $this->assertEquals(
-                       '',
+               $this->assertNull(
                        $db->getDBname(),
                        'Null domain ID handle used'
                );
-               $this->assertEquals(
+               $this->assertSame(
                        '',
                        $db->tablePrefix(),
                        'Main domain ID handle used; prefix is empty though'
@@@ -555,7 -554,7 +554,7 @@@
                /** @var IMaintainableDatabase $db */
                $db = $lb->getConnection( DB_MASTER, [], '' );
  
-               $this->assertEquals( '', $db->getDomainID(), "Null domain used" );
+               $this->assertSame( '', $db->getDomainID(), "Null domain used" );
  
                $this->assertEquals(
                        $this->quoteTable( $db, 'page' ),
@@@ -717,7 -716,7 +716,7 @@@
                $lb->forEachOpenConnection( function () use ( &$n ) {
                        ++$n;
                } );
 -              $this->assertEquals( 0, $n, "Connections closed" );
 +              $this->assertSame( 0, $n, "Connections closed" );
  
                $conn2 = $lb->getConnectionRef( DB_MASTER );
                $this->assertEquals(