$this->assertSame( $slotA, $slots->getSlot( 'some' ) );
$this->assertSame( [ 'some' => $slotA ], $slots->getSlots() );
$slotB = SlotRecord::newUnsaved( 'other', new WikitextContent( 'B' ) );
$slots->setSlot( $slotB );
$this->assertSame( $slotA, $slots->getSlot( 'some' ) );
$this->assertSame( [ 'some' => $slotA ], $slots->getSlots() );
$slotB = SlotRecord::newUnsaved( 'other', new WikitextContent( 'B' ) );
$slots->setSlot( $slotB );