diff --git a/src/ByPropertyIdArray.php b/src/ByPropertyIdArray.php
deleted file mode 100644
index fe52e95d..00000000
--- a/src/ByPropertyIdArray.php
+++ /dev/null
@@ -1,487 +0,0 @@
-<?php
-
-namespace Wikibase\DataModel;
-
-use ArrayObject;
-use OutOfBoundsException;
-use RuntimeException;
-use Wikibase\DataModel\Entity\PropertyId;
-
-/**
- * Helper for managing objects indexed by property id.
- *
- * This is a light weight alternative approach to using something
- * like GenericArrayObject with the advantages that no extra interface
- * is needed and that indexing does not happen automatically.
- *
- * Lack of automatic indexing means that you will need to call the
- * buildIndex method before doing any look-ups.
- *
- * Since no extra interface is used, the user is responsible for only
- * adding objects that have a getPropertyId method that returns either
- * a string or integer when called with no arguments.
- *
- * Objects may be added or moved within the structure. Absolute indices (indices according to the
- * flat list of objects) may be specified to add or move objects. These management operations take
- * the property grouping into account. Adding or moving objects outside their "property groups"
- * shifts the whole group towards that index.
- *
- * Example of moving an object within its "property group":
- * o1 (p1)                           o1 (p1)
- * o2 (p2)                       /-> o3 (p2)
- * o3 (p2) ---> move to index 1 -/   o2 (p2)
- *
- * Example of moving an object that triggers moving the whole "property group":
- * o1 (p1)                       /-> o3 (p2)
- * o2 (p2)                       |   o2 (p2)
- * o3 (p2) ---> move to index 0 -/   o1 (p1)
- *
- * @since 0.2
- *
- * @licence GNU GPL v2+
- * @author H. Snater < mediawiki@snater.com >
- */
-class ByPropertyIdArray extends ArrayObject {
-
-	/**
-	 * @var array[]|null
-	 */
-	private $byId = null;
-
-	/**
-	 * @see ArrayObject::__construct
-	 *
-	 * @param array|object|null $input
-	 */
-	public function __construct( $input = null ) {
-		parent::__construct( (array)$input );
-	}
-
-	/**
-	 * Builds the index for doing look-ups by property id.
-	 *
-	 * @since 0.2
-	 */
-	public function buildIndex() {
-		$this->byId = array();
-
-		foreach ( $this as $object ) {
-			$propertyId = $object->getPropertyId()->getSerialization();
-
-			if ( !array_key_exists( $propertyId, $this->byId ) ) {
-				$this->byId[$propertyId] = array();
-			}
-
-			$this->byId[$propertyId][] = $object;
-		}
-	}
-
-	/**
-	 * Checks whether id indexed array has been generated.
-	 *
-	 * @throws RuntimeException
-	 */
-	private function assertIndexIsBuild() {
-		if ( $this->byId === null ) {
-			throw new RuntimeException( 'Index not build, call buildIndex first' );
-		}
-	}
-
-	/**
-	 * Returns the property ids used for indexing.
-	 *
-	 * @since 0.2
-	 *
-	 * @return PropertyId[]
-	 * @throws RuntimeException
-	 */
-	public function getPropertyIds() {
-		$this->assertIndexIsBuild();
-
-		return array_map(
-			function( $serializedPropertyId ) {
-				return new PropertyId( $serializedPropertyId );
-			},
-			array_keys( $this->byId )
-		);
-	}
-
-	/**
-	 * Returns the objects featuring the provided property id in the index.
-	 *
-	 * @since 0.2
-	 *
-	 * @param PropertyId $propertyId
-	 *
-	 * @throws OutOfBoundsException
-	 * @throws RuntimeException
-	 * @return object[]
-	 */
-	public function getByPropertyId( PropertyId $propertyId ) {
-		$this->assertIndexIsBuild();
-
-		if ( !( array_key_exists( $propertyId->getSerialization(), $this->byId ) ) ) {
-			throw new OutOfBoundsException( "Object with propertyId \"$propertyId\" not found" );
-		}
-
-		return $this->byId[$propertyId->getSerialization()];
-	}
-
-	/**
-	 * Returns the absolute index of an object or false if the object could not be found.
-	 * @since 0.5
-	 *
-	 * @param object $object
-	 *
-	 * @return bool|int
-	 * @throws RuntimeException
-	 */
-	public function getFlatArrayIndexOfObject( $object ) {
-		$this->assertIndexIsBuild();
-
-		$i = 0;
-		foreach ( $this as $o ) {
-			if ( $o === $object ) {
-				return $i;
-			}
-			$i++;
-		}
-		return false;
-	}
-
-	/**
-	 * Returns the objects in a flat array (using the indexed form for generating the array).
-	 * @since 0.5
-	 *
-	 * @return object[]
-	 * @throws RuntimeException
-	 */
-	public function toFlatArray() {
-		$this->assertIndexIsBuild();
-
-		$array = array();
-		foreach ( $this->byId as $objects ) {
-			$array = array_merge( $array, $objects );
-		}
-		return $array;
-	}
-
-	/**
-	 * Returns the absolute numeric indices of objects featuring the same property id.
-	 *
-	 * @param PropertyId $propertyId
-	 *
-	 * @throws RuntimeException
-	 * @return int[]
-	 */
-	private function getFlatArrayIndices( PropertyId $propertyId ) {
-		$this->assertIndexIsBuild();
-
-		$propertyIndices = array();
-		$i = 0;
-
-		foreach ( $this->byId as $serializedPropertyId => $objects ) {
-			if ( $serializedPropertyId === $propertyId->getSerialization() ) {
-				$propertyIndices = range( $i, $i + count( $objects ) - 1 );
-				break;
-			} else {
-				$i += count( $objects );
-			}
-		}
-
-		return $propertyIndices;
-	}
-
-	/**
-	 * Moves an object within its "property group".
-	 *
-	 * @param object $object
-	 * @param int $toIndex Absolute index within a "property group".
-	 *
-	 * @throws OutOfBoundsException
-	 */
-	private function moveObjectInPropertyGroup( $object, $toIndex ) {
-		$currentIndex = $this->getFlatArrayIndexOfObject( $object );
-
-		if ( $toIndex === $currentIndex ) {
-			return;
-		}
-
-		$propertyId = $object->getPropertyId();
-
-		$numericIndices = $this->getFlatArrayIndices( $propertyId );
-		$lastIndex = $numericIndices[count( $numericIndices ) - 1];
-
-		if ( $toIndex > $lastIndex + 1 || $toIndex < $numericIndices[0] ) {
-			throw new OutOfBoundsException( 'Object cannot be moved to ' . $toIndex );
-		}
-
-		if ( $toIndex >= $lastIndex ) {
-			$this->moveObjectToEndOfPropertyGroup( $object );
-		} else {
-			$this->removeObject( $object );
-
-			$propertyGroup = array_combine(
-				$this->getFlatArrayIndices( $propertyId ),
-				$this->getByPropertyId( $propertyId )
-			);
-
-			$insertBefore = $propertyGroup[$toIndex];
-			$this->insertObjectAtIndex( $object, $this->getFlatArrayIndexOfObject( $insertBefore ) );
-		}
-	}
-
-	/**
-	 * Moves an object to the end of its "property group".
-	 *
-	 * @param object $object
-	 */
-	private function moveObjectToEndOfPropertyGroup( $object ) {
-		$this->removeObject( $object );
-
-		/** @var PropertyId $propertyId */
-		$propertyId = $object->getPropertyId();
-		$propertyIdSerialization = $propertyId->getSerialization();
-
-		$propertyGroup = in_array( $propertyIdSerialization, $this->getPropertyIds() )
-			? $this->getByPropertyId( $propertyId )
-			: array();
-
-		$propertyGroup[] = $object;
-		$this->byId[$propertyIdSerialization] = $propertyGroup;
-
-		$this->exchangeArray( $this->toFlatArray() );
-	}
-
-	/**
-	 * Removes an object from the array structures.
-	 *
-	 * @param object $object
-	 */
-	private function removeObject( $object ) {
-		$flatArray = $this->toFlatArray();
-		$this->exchangeArray( $flatArray );
-		$this->offsetUnset( array_search( $object, $flatArray ) );
-		$this->buildIndex();
-	}
-
-	/**
-	 * Inserts an object at a specific index.
-	 *
-	 * @param object $object
-	 * @param int $index Absolute index within the flat list of objects.
-	 */
-	private function insertObjectAtIndex( $object, $index ) {
-		$flatArray = $this->toFlatArray();
-
-		$this->exchangeArray( array_merge(
-			array_slice( $flatArray, 0, $index ),
-			array( $object ),
-			array_slice( $flatArray, $index )
-		) );
-
-		$this->buildIndex();
-	}
-
-	/**
-	 * @param PropertyId $propertyId
-	 * @param int $toIndex
-	 */
-	private function movePropertyGroup( PropertyId $propertyId, $toIndex ) {
-		if ( $this->getPropertyGroupIndex( $propertyId ) === $toIndex ) {
-			return;
-		}
-
-		$insertBefore = null;
-
-		$oldIndex = $this->getPropertyGroupIndex( $propertyId );
-		$byIdClone = $this->byId;
-
-		// Remove "property group" to calculate the groups new index:
-		unset( $this->byId[$propertyId->getSerialization()] );
-
-		if ( $toIndex > $oldIndex ) {
-			// If the group shall be moved towards the bottom, the number of objects within the
-			// group needs to be subtracted from the absolute toIndex:
-			$toIndex -= count( $byIdClone[$propertyId->getSerialization()] );
-		}
-
-		foreach ( $this->getPropertyIds() as $pId ) {
-			// Accepting other than the exact index by using <= letting the "property group" "latch"
-			// in the next slot.
-			if ( $toIndex <= $this->getPropertyGroupIndex( $pId ) ) {
-				$insertBefore = $pId;
-				break;
-			}
-		}
-
-		$serializedPropertyId = $propertyId->getSerialization();
-		$this->byId = array();
-
-		foreach ( $byIdClone as $serializedPId => $objects ) {
-			$pId = new PropertyId( $serializedPId );
-			if ( $pId->equals( $propertyId ) ) {
-				continue;
-			} elseif ( $pId->equals( $insertBefore ) ) {
-				$this->byId[$serializedPropertyId] = $byIdClone[$serializedPropertyId];
-			}
-			$this->byId[$serializedPId] = $objects;
-		}
-
-		if ( $insertBefore === null ) {
-			$this->byId[$serializedPropertyId] = $byIdClone[$serializedPropertyId];
-		}
-
-		$this->exchangeArray( $this->toFlatArray() );
-	}
-
-	/**
-	 * Returns the index of a "property group" (the first object in the flat array that features
-	 * the specified property). Returns false if property id could not be found.
-	 *
-	 * @param PropertyId $propertyId
-	 *
-	 * @return bool|int
-	 */
-	private function getPropertyGroupIndex( PropertyId $propertyId ) {
-		$i = 0;
-
-		foreach ( $this->byId as $serializedPropertyId => $objects ) {
-			$pId = new PropertyId( $serializedPropertyId );
-			if ( $pId->equals( $propertyId ) ) {
-				return $i;
-			}
-			$i += count( $objects );
-		}
-
-		return false;
-	}
-
-	/**
-	 * Moves an existing object to a new index. Specifying an index outside the object's "property
-	 * group" will move the object to the edge of the "property group" and shift the whole group
-	 * to achieve the designated index for the object to move.
-	 * @since 0.5
-	 *
-	 * @param object $object
-	 * @param int $toIndex Absolute index where to move the object to.
-	 *
-	 * @throws OutOfBoundsException
-	 * @throws RuntimeException
-	 */
-	public function moveObjectToIndex( $object, $toIndex ) {
-		$this->assertIndexIsBuild();
-
-		if ( !in_array( $object, $this->toFlatArray() ) ) {
-			throw new OutOfBoundsException( 'Object not present in array' );
-		} elseif ( $toIndex < 0 || $toIndex > count( $this ) ) {
-			throw new OutOfBoundsException( 'Specified index is out of bounds' );
-		} elseif ( $this->getFlatArrayIndexOfObject( $object ) === $toIndex ) {
-			return;
-		}
-
-		// Determine whether to simply reindex the object within its "property group":
-		$propertyIndices = $this->getFlatArrayIndices( $object->getPropertyId() );
-
-		if ( in_array( $toIndex, $propertyIndices ) ) {
-			$this->moveObjectInPropertyGroup( $object, $toIndex );
-		} else {
-			$edgeIndex = ( $toIndex <= $propertyIndices[0] )
-				? $propertyIndices[0]
-				: $propertyIndices[count( $propertyIndices ) - 1];
-
-			$this->moveObjectInPropertyGroup( $object, $edgeIndex );
-			$this->movePropertyGroup( $object->getPropertyId(), $toIndex );
-		}
-
-		$this->exchangeArray( $this->toFlatArray() );
-	}
-
-	/**
-	 * Adds an object at a specific index. If no index is specified, the object will be append to
-	 * the end of its "property group" or - if no objects featuring the same property exist - to the
-	 * absolute end of the array.
-	 * Specifying an index outside a "property group" will place the new object at the specified
-	 * index with the existing "property group" objects being shifted towards the new object.
-	 *
-	 * @since 0.5
-	 *
-	 * @param object $object
-	 * @param int|null $index Absolute index where to place the new object.
-	 *
-	 * @throws RuntimeException
-	 */
-	public function addObjectAtIndex( $object, $index = null ) {
-		$this->assertIndexIsBuild();
-
-		$propertyId = $object->getPropertyId();
-		$validIndices = $this->getFlatArrayIndices( $propertyId );
-
-		if ( count( $this ) === 0 ) {
-			// Array is empty, just append object.
-			$this->append( $object );
-		} elseif ( empty( $validIndices ) ) {
-			// No objects featuring that property exist. The object may be inserted at a place
-			// between existing "property groups".
-			$this->append( $object );
-			if ( $index !== null ) {
-				$this->buildIndex();
-				$this->moveObjectToIndex( $object, $index );
-			}
-		} else {
-			// Objects featuring the same property as the object which is about to be added already
-			// exist in the array.
-			$this->addObjectToPropertyGroup( $object, $index );
-		}
-
-		$this->buildIndex();
-	}
-
-	/**
-	 * Adds an object to an existing property group at the specified absolute index.
-	 *
-	 * @param object $object
-	 * @param int|null $index
-	 *
-	 * @throws OutOfBoundsException
-	 */
-	private function addObjectToPropertyGroup( $object, $index = null ) {
-		/** @var PropertyId $propertyId */
-		$propertyId = $object->getPropertyId();
-		$validIndices = $this->getFlatArrayIndices( $propertyId );
-
-		if ( empty( $validIndices ) ) {
-			throw new OutOfBoundsException( 'No objects featuring the object\'s property exist' );
-		}
-
-		// Add index to allow placing object after the last object of the "property group":
-		$validIndices[] = $validIndices[count( $validIndices ) - 1] + 1;
-
-		if ( $index === null ) {
-			// If index is null, append object to "property group".
-			$index = $validIndices[count( $validIndices ) - 1];
-		}
-
-		if ( in_array( $index, $validIndices ) ) {
-			// Add object at index within "property group".
-			$this->byId[$propertyId->getSerialization()][] = $object;
-			$this->exchangeArray( $this->toFlatArray() );
-			$this->moveObjectToIndex( $object, $index );
-
-		} else {
-			// Index is out of the "property group"; The whole group needs to be moved.
-			$this->movePropertyGroup( $propertyId, $index );
-
-			// Move new object to the edge of the "property group" to receive its designated
-			// index:
-			if ( $index < $validIndices[0] ) {
-				array_unshift( $this->byId[$propertyId->getSerialization()], $object );
-			} else {
-				$this->byId[$propertyId->getSerialization()][] = $object;
-			}
-		}
-
-		$this->exchangeArray( $this->toFlatArray() );
-	}
-
-}
diff --git a/tests/unit/ByPropertyIdArrayTest.php b/tests/unit/ByPropertyIdArrayTest.php
deleted file mode 100644
index cb79bfe5..00000000
--- a/tests/unit/ByPropertyIdArrayTest.php
+++ /dev/null
@@ -1,400 +0,0 @@
-<?php
-
-namespace Wikibase\DataModel\Tests;
-
-use ArrayObject;
-use DataValues\StringValue;
-use ReflectionClass;
-use ReflectionMethod;
-use Wikibase\DataModel\ByPropertyIdArray;
-use Wikibase\DataModel\Entity\PropertyId;
-use Wikibase\DataModel\PropertyIdProvider;
-use Wikibase\DataModel\Snak\PropertyNoValueSnak;
-use Wikibase\DataModel\Snak\PropertySomeValueSnak;
-use Wikibase\DataModel\Snak\PropertyValueSnak;
-use Wikibase\DataModel\Snak\Snak;
-use Wikibase\DataModel\Statement\Statement;
-
-/**
- * @covers Wikibase\DataModel\ByPropertyIdArray
- *
- * @group Wikibase
- * @group WikibaseDataModel
- * @group ByPropertyIdArrayTest
- *
- * @licence GNU GPL v2+
- * @author Jeroen De Dauw < jeroendedauw@gmail.com >
- * @author H. Snater < mediawiki@snater.com >
- */
-class ByPropertyIdArrayTest extends \PHPUnit_Framework_TestCase {
-
-	public function testArrayObjectNotConstructedFromObject() {
-		$statement1 = new Statement( new PropertyNoValueSnak( 1 ) );
-		$statement1->setGuid( '1' );
-		$statement2 = new Statement( new PropertyNoValueSnak( 2 ) );
-		$statement2->setGuid( '2' );
-
-		$object = new ArrayObject();
-		$object->append( $statement1 );
-
-		$byPropertyIdArray = new ByPropertyIdArray( $object );
-		// According to the documentation append() "cannot be called when the ArrayObject was
-		// constructed from an object." This test makes sure it was not constructed from an object.
-		$byPropertyIdArray->append( $statement2 );
-
-		$this->assertCount( 2, $byPropertyIdArray );
-	}
-
-	/**
-	 * Returns an accessible ReflectionMethod of ByPropertyIdArray.
-	 *
-	 * @param string $methodName
-	 * @return ReflectionMethod
-	 */
-	protected static function getMethod( $methodName ) {
-		$class = new ReflectionClass( 'Wikibase\DataModel\ByPropertyIdArray' );
-		$method = $class->getMethod( $methodName );
-		$method->setAccessible( true );
-		return $method;
-	}
-
-	public function listProvider() {
-		$lists = array();
-
-		$snaks = array(
-			new PropertyNoValueSnak( new PropertyId( 'P42' ) ),
-			new PropertySomeValueSnak( new PropertyId( 'P42' ) ),
-			new PropertySomeValueSnak( new PropertyId( 'P10' ) ),
-			new PropertyValueSnak( new PropertyId( 'P10' ), new StringValue( 'ohi' ) ),
-			new PropertySomeValueSnak( new PropertyId( 'P1' ) ),
-		);
-
-		$lists[] = $snaks;
-
-		$lists[] = array_map(
-			function( Snak $snak ) {
-				return new Statement( $snak );
-			},
-			$snaks
-		);
-
-		$argLists = array();
-
-		foreach ( $lists as $list ) {
-			$argLists[] = array( $list );
-		}
-
-		return $argLists;
-	}
-
-	/**
-	 * @return Statement[]
-	 */
-	protected function statementsProvider() {
-		$snaks = array(
-			new PropertyNoValueSnak( new PropertyId( 'P1' ) ),
-			new PropertySomeValueSnak( new PropertyId( 'P1' ) ),
-			new PropertyValueSnak( new PropertyId( 'P2' ), new StringValue( 'a' ) ),
-			new PropertyValueSnak( new PropertyId( 'P2' ), new StringValue( 'b' ) ),
-			new PropertyValueSnak( new PropertyId( 'P2' ), new StringValue( 'c' ) ),
-			new PropertySomeValueSnak( new PropertyId( 'P3' ) ),
-		);
-
-		return array_map(
-			function( Snak $snak ) {
-				return new Statement( $snak );
-			},
-			$snaks
-		);
-	}
-
-	/**
-	 * @dataProvider listProvider
-	 * @param PropertyIdProvider[] $objects
-	 */
-	public function testGetIds( array $objects ) {
-		$indexedArray = new ByPropertyIdArray( $objects );
-
-		$expected = array();
-
-		foreach ( $objects as $object ) {
-			$expected[] = $object->getPropertyId();
-		}
-
-		$expected = array_unique( $expected );
-
-		$indexedArray->buildIndex();
-
-		$this->assertEquals(
-			array_values( $expected ),
-			array_values( $indexedArray->getPropertyIds() )
-		);
-	}
-
-	/**
-	 * @dataProvider listProvider
-	 * @param PropertyIdProvider[] $objects
-	 */
-	public function testGetById( array $objects ) {
-		$indexedArray = new ByPropertyIdArray( $objects );
-
-		$ids = array();
-
-		foreach ( $objects as $object ) {
-			$ids[] = $object->getPropertyId();
-		}
-
-		$ids = array_unique( $ids );
-
-		$indexedArray->buildIndex();
-
-		$allObtainedObjects = array();
-
-		foreach ( $ids as $id ) {
-			foreach ( $indexedArray->getByPropertyId( $id ) as $obtainedObject ) {
-				$allObtainedObjects[] = $obtainedObject;
-				$this->assertEquals( $id, $obtainedObject->getPropertyId() );
-			}
-		}
-
-		$this->assertEquals(
-			array_values( $objects ),
-			array_values( $allObtainedObjects )
-		);
-	}
-
-	/**
-	 * @dataProvider listProvider
-	 * @param PropertyIdProvider[] $objects
-	 */
-	public function testRemoveObject( array $objects ) {
-		$lastIndex = count( $objects ) - 1;
-		$indexedArray = new ByPropertyIdArray( $objects );
-		$indexedArray->buildIndex();
-
-		$removeObject = self::getMethod( 'removeObject' );
-
-		$removeObject->invokeArgs( $indexedArray, array( $objects[0] ) );
-		$removeObject->invokeArgs( $indexedArray, array( $objects[$lastIndex] ) );
-
-		$this->assertFalse(
-			in_array( $objects[0], $indexedArray->getByPropertyId( $objects[0]->getPropertyId() ) )
-		);
-
-		$this->assertFalse( in_array(
-			$objects[$lastIndex],
-			$indexedArray->getByPropertyId( $objects[1]->getPropertyId() )
-		) );
-
-		$this->assertFalse( in_array( $objects[0], $indexedArray->toFlatArray() ) );
-		$this->assertFalse( in_array( $objects[$lastIndex], $indexedArray->toFlatArray() ) );
-	}
-
-	public function testGetByNotSetIdThrowsException() {
-		$indexedArray = new ByPropertyIdArray();
-		$indexedArray->buildIndex();
-
-		$this->setExpectedException( 'OutOfBoundsException' );
-
-		$indexedArray->getByPropertyId( PropertyId::newFromNumber( 9000 ) );
-	}
-
-	public function testNotBuildExceptionIsThrownForByPropertyId() {
-		$indexedArray = new ByPropertyIdArray();
-
-		$this->setExpectedException( 'RuntimeException' );
-		$indexedArray->getByPropertyId( PropertyId::newFromNumber( 9000 ) );
-	}
-
-	public function testNotBuildExceptionIsThrownForGetPropertyIds() {
-		$indexedArray = new ByPropertyIdArray();
-
-		$this->setExpectedException( 'RuntimeException' );
-		$indexedArray->getPropertyIds();
-	}
-
-	/**
-	 * @dataProvider listProvider
-	 */
-	public function testGetFlatArrayIndexOfObject( array $objects ) {
-		$indexedArray = new ByPropertyIdArray( $objects );
-		$indexedArray->buildIndex();
-
-		$indicesSource = array();
-		$indicesDestination = array();
-
-		$i = 0;
-		foreach ( $objects as $object ) {
-			$indicesSource[$i++] = $object;
-			$indicesDestination[$indexedArray->getFlatArrayIndexOfObject( $object )] = $object;
-		}
-
-		$this->assertEquals( $indicesSource, $indicesDestination );
-	}
-
-	/**
-	 * @dataProvider listProvider
-	 */
-	public function testToFlatArray( array $objects ) {
-		$indexedArray = new ByPropertyIdArray( $objects );
-		$indexedArray->buildIndex();
-
-		$this->assertEquals( $objects, $indexedArray->toFlatArray() );
-	}
-
-	public function moveProvider() {
-		$c = $this->statementsProvider();
-		$argLists = array();
-
-		$argLists[] = array( $c, $c[0], 0, $c );
-		$argLists[] = array( $c, $c[0], 1, array( $c[1], $c[0], $c[2], $c[3], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[0], 2, array( $c[1], $c[0], $c[2], $c[3], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[0], 3, array( $c[2], $c[3], $c[4], $c[1], $c[0], $c[5] ) );
-		$argLists[] = array( $c, $c[0], 4, array( $c[2], $c[3], $c[4], $c[1], $c[0], $c[5] ) );
-		$argLists[] = array( $c, $c[0], 5, array( $c[2], $c[3], $c[4], $c[1], $c[0], $c[5] ) );
-		$argLists[] = array( $c, $c[0], 6, array( $c[2], $c[3], $c[4], $c[5], $c[1], $c[0] ) );
-
-		$argLists[] = array( $c, $c[1], 0, array( $c[1], $c[0], $c[2], $c[3], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[1], 1, $c );
-		$argLists[] = array( $c, $c[1], 2, $c );
-		$argLists[] = array( $c, $c[1], 3, array( $c[2], $c[3], $c[4], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[1], 4, array( $c[2], $c[3], $c[4], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[1], 5, array( $c[2], $c[3], $c[4], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[1], 6, array( $c[2], $c[3], $c[4], $c[5], $c[0], $c[1] ) );
-
-		$argLists[] = array( $c, $c[2], 0, array( $c[2], $c[3], $c[4], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[2], 1, $c );
-		$argLists[] = array( $c, $c[2], 2, $c );
-		$argLists[] = array( $c, $c[2], 3, array( $c[0], $c[1], $c[3], $c[2], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[2], 4, array( $c[0], $c[1], $c[3], $c[4], $c[2], $c[5] ) );
-		$argLists[] = array( $c, $c[2], 5, array( $c[0], $c[1], $c[3], $c[4], $c[2], $c[5] ) );
-		$argLists[] = array( $c, $c[2], 6, array( $c[0], $c[1], $c[5], $c[3], $c[4], $c[2] ) );
-
-		$argLists[] = array( $c, $c[3], 0, array( $c[3], $c[2], $c[4], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[3], 1, array( $c[0], $c[1], $c[3], $c[2], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[3], 2, array( $c[0], $c[1], $c[3], $c[2], $c[4], $c[5] ) );
-		$argLists[] = array( $c, $c[3], 3, $c );
-		$argLists[] = array( $c, $c[3], 4, array( $c[0], $c[1], $c[2], $c[4], $c[3], $c[5] ) );
-		$argLists[] = array( $c, $c[3], 5, array( $c[0], $c[1], $c[2], $c[4], $c[3], $c[5] ) );
-		$argLists[] = array( $c, $c[3], 6, array( $c[0], $c[1], $c[5], $c[2], $c[4], $c[3] ) );
-
-		$argLists[] = array( $c, $c[4], 0, array( $c[4], $c[2], $c[3], $c[0], $c[1], $c[5] ) );
-		$argLists[] = array( $c, $c[4], 1, array( $c[0], $c[1], $c[4], $c[2], $c[3], $c[5] ) );
-		$argLists[] = array( $c, $c[4], 2, array( $c[0], $c[1], $c[4], $c[2], $c[3], $c[5] ) );
-		$argLists[] = array( $c, $c[4], 3, array( $c[0], $c[1], $c[2], $c[4], $c[3], $c[5] ) );
-		$argLists[] = array( $c, $c[4], 4, $c );
-		$argLists[] = array( $c, $c[4], 5, $c );
-		$argLists[] = array( $c, $c[4], 6, array( $c[0], $c[1], $c[5], $c[2], $c[3], $c[4] ) );
-
-		$argLists[] = array( $c, $c[5], 0, array( $c[5], $c[0], $c[1], $c[2], $c[3], $c[4] ) );
-		$argLists[] = array( $c, $c[5], 1, array( $c[0], $c[1], $c[5], $c[2], $c[3], $c[4] ) );
-		$argLists[] = array( $c, $c[5], 2, array( $c[0], $c[1], $c[5], $c[2], $c[3], $c[4] ) );
-		$argLists[] = array( $c, $c[5], 3, $c );
-		$argLists[] = array( $c, $c[5], 4, $c );
-		$argLists[] = array( $c, $c[5], 5, $c );
-		$argLists[] = array( $c, $c[5], 6, $c );
-
-		return $argLists;
-	}
-
-	/**
-	 * @dataProvider moveProvider
-	 * @param object[] $objectsSource
-	 * @param object $object
-	 * @param int $toIndex
-	 * @param object[] $objectsDestination
-	 */
-	public function testMoveObjectToIndex(
-		array $objectsSource,
-		$object,
-		$toIndex,
-		array $objectsDestination
-	) {
-		$indexedArray = new ByPropertyIdArray( $objectsSource );
-		$indexedArray->buildIndex();
-
-		$indexedArray->moveObjectToIndex( $object, $toIndex );
-
-		// Not using $indexedArray->toFlatArray() here to test whether native array has been
-		// exchanged:
-		$reindexedArray = array();
-		foreach ( $indexedArray as $o ) {
-			$reindexedArray[] = $o;
-		}
-
-		$this->assertEquals( $objectsDestination, $reindexedArray );
-	}
-
-	public function testMoveThrowingOutOfBoundsExceptionIfObjectNotPresent() {
-		$statements = $this->statementsProvider();
-		$indexedArray = new ByPropertyIdArray( $statements );
-		$indexedArray->buildIndex();
-
-		$this->setExpectedException( 'OutOfBoundsException' );
-
-		$indexedArray->moveObjectToIndex( new Statement( new PropertyNoValueSnak( new PropertyId( 'P9999' ) ) ), 0 );
-	}
-
-	public function testMoveThrowingOutOfBoundsExceptionOnInvalidIndex() {
-		$statements = $this->statementsProvider();
-		$indexedArray = new ByPropertyIdArray( $statements );
-		$indexedArray->buildIndex();
-
-		$this->setExpectedException( 'OutOfBoundsException' );
-
-		$indexedArray->moveObjectToIndex( $statements[0], 9999 );
-	}
-
-	public function addProvider() {
-		$c = $this->statementsProvider();
-
-		$argLists = array();
-
-		$argLists[] = array( array(), $c[0], null, array( $c[0] ) );
-		$argLists[] = array( array(), $c[0], 1, array( $c[0] ) );
-		$argLists[] = array( array( $c[0] ), $c[2], 0, array( $c[2], $c[0] ) );
-		$argLists[] = array( array( $c[2], $c[1] ), $c[0], 0, array( $c[0], $c[1], $c[2] ) );
-		$argLists[] = array(
-			array( $c[0], $c[1], $c[3] ),
-			$c[5],
-			1,
-			array( $c[0], $c[1], $c[5], $c[3] )
-		);
-		$argLists[] = array(
-			array( $c[0], $c[1], $c[5], $c[3] ),
-			$c[2],
-			2,
-			array( $c[0], $c[1], $c[2], $c[3], $c[5] )
-		);
-		$argLists[] = array(
-			array( $c[0], $c[1], $c[2], $c[3], $c[5] ),
-			$c[4],
-			null,
-			array( $c[0], $c[1], $c[2], $c[3], $c[4], $c[5] )
-		);
-
-		return $argLists;
-	}
-
-	/**
-	 * @dataProvider addProvider
-	 * @param object[] $objectsSource
-	 * @param object $object
-	 * @param int|null $index
-	 * @param object[] $objectsDestination
-	 */
-	public function testAddObjectAtIndex(
-		array $objectsSource,
-		$object,
-		$index,
-		array $objectsDestination
-	) {
-		$indexedArray = new ByPropertyIdArray( $objectsSource );
-		$indexedArray->buildIndex();
-
-		$indexedArray->addObjectAtIndex( $object, $index );
-
-		$this->assertEquals( $objectsDestination, $indexedArray->toFlatArray() );
-	}
-
-}