diff --git src/wp-includes/class-wp-list-util.php src/wp-includes/class-wp-list-util.php
new file mode 100644
index 0000000..0820bb3
--- /dev/null
+++ src/wp-includes/class-wp-list-util.php
@@ -0,0 +1,260 @@
+<?php
+/**
+ * WordPress List utility class
+ *
+ * @package WordPress
+ * @since 4.7.0
+ */
+
+/**
+ * List utility.
+ *
+ * Utility class to handle operations on an array of objects.
+ *
+ * @since 4.7.0
+ */
+class WP_List_Util {
+	/**
+	 * The input array.
+	 *
+	 * @since 4.7.0
+	 * @access private
+	 * @var array
+	 */
+	private $input = array();
+
+	/**
+	 * The output array.
+	 *
+	 * @since 4.7.0
+	 * @access private
+	 * @var array
+	 */
+	private $output = array();
+
+	/**
+	 * Temporary arguments for sorting.
+	 *
+	 * @since 4.7.0
+	 * @access private
+	 * @var array
+	 */
+	private $orderby = array();
+
+	/**
+	 * Constructor.
+	 *
+	 * Sets the input array.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param array $input Array to perform operations on.
+	 */
+	public function __construct( $input ) {
+		$this->output = $this->input = $input;
+	}
+
+	/**
+	 * Returns the original input array.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 *
+	 * @return array The input array.
+	 */
+	public function get_input() {
+		return $this->input;
+	}
+
+	/**
+	 * Returns the output array.
+	 *
+	 * @since 4.7.0
+	 * @access public
+	 *
+	 * @return array The output array.
+	 */
+	public function get_output() {
+		return $this->output;
+	}
+
+	/**
+	 * Filters the list, based on a set of key => value arguments.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param array  $args     Optional. An array of key => value arguments to match
+	 *                         against each object. Default empty array.
+	 * @param string $operator Optional. The logical operation to perform. 'AND' means
+	 *                         all elements from the array must match. 'OR' means only
+	 *                         one element needs to match. 'NOT' means no elements may
+	 *                         match. Default 'AND'.
+	 * @return array Array of found values.
+	 */
+	public function filter( $args = array(), $operator = 'AND' ) {
+		if ( empty( $args ) ) {
+			return $this->output;
+		}
+
+		$operator = strtoupper( $operator );
+
+		if ( ! in_array( $operator, array( 'AND', 'OR', 'NOT' ), true ) ) {
+			return array();
+		}
+
+		$count = count( $args );
+		$filtered = array();
+
+		foreach ( $this->output as $key => $obj ) {
+			$to_match = (array) $obj;
+
+			$matched = 0;
+			foreach ( $args as $m_key => $m_value ) {
+				if ( array_key_exists( $m_key, $to_match ) && $m_value == $to_match[ $m_key ] ) {
+					$matched++;
+				}
+			}
+
+			if ( ( 'AND' == $operator && $matched == $count )
+			  || ( 'OR' == $operator && $matched > 0 )
+			  || ( 'NOT' == $operator && 0 == $matched ) ) {
+				$filtered[$key] = $obj;
+			}
+		}
+
+		$this->output = $filtered;
+
+		return $this->output;
+	}
+
+	/**
+	 * Plucks a certain field out of each object in the list.
+	 *
+	 * This has the same functionality and prototype of
+	 * array_column() (PHP 5.5) but also supports objects.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param int|string $field     Field from the object to place instead of the entire object
+	 * @param int|string $index_key Optional. Field from the object to use as keys for the new array.
+	 *                              Default null.
+	 * @return array Array of found values. If `$index_key` is set, an array of found values with keys
+	 *               corresponding to `$index_key`. If `$index_key` is null, array keys from the original
+	 *               `$list` will be preserved in the results.
+	 */
+	public function pluck( $field, $index_key = null ) {
+		if ( ! $index_key ) {
+			/*
+			 * This is simple. Could at some point wrap array_column()
+			 * if we knew we had an array of arrays.
+			 */
+			foreach ( $this->output as $key => $value ) {
+				if ( is_object( $value ) ) {
+					$this->output[ $key ] = $value->$field;
+				} else {
+					$this->output[ $key ] = $value[ $field ];
+				}
+			}
+			return $this->output;
+		}
+
+		/*
+		 * When index_key is not set for a particular item, push the value
+		 * to the end of the stack. This is how array_column() behaves.
+		 */
+		$newlist = array();
+		foreach ( $this->output as $value ) {
+			if ( is_object( $value ) ) {
+				if ( isset( $value->$index_key ) ) {
+					$newlist[ $value->$index_key ] = $value->$field;
+				} else {
+					$newlist[] = $value->$field;
+				}
+			} else {
+				if ( isset( $value[ $index_key ] ) ) {
+					$newlist[ $value[ $index_key ] ] = $value[ $field ];
+				} else {
+					$newlist[] = $value[ $field ];
+				}
+			}
+		}
+
+		$this->output = $newlist;
+
+		return $this->output;
+	}
+
+	/**
+	 * Sorts the list, based on one or more orderby arguments.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param string|array $orderby Optional. Either the field name to order by or an array
+	 *                              of multiple orderby fields as $orderby => $order.
+	 * @param string       $order   Optional. Either 'ASC' or 'DESC'. Only used if $orderby
+	 *                              is a string.
+	 * @return array The sorted array.
+	 */
+	public function sort( $orderby = array(), $order = 'ASC' ) {
+		if ( empty( $orderby ) ) {
+			return $this->output;
+		}
+
+		if ( is_string( $orderby ) ) {
+			$orderby = array( $orderby => $order );
+		}
+
+		foreach ( $orderby as $field => $direction ) {
+			$orderby[ $field ] = 'DESC' === strtoupper( $direction ) ? 'DESC' : 'ASC';
+		}
+
+		$this->orderby = $orderby;
+
+		usort( $this->output, array( $this, 'sort_callback' ) );
+
+		$this->orderby = array();
+
+		return $this->output;
+	}
+
+	/**
+	 * Callback to sort the list by specific fields.
+	 *
+	 * @since 4.7.0
+	 * @access private
+	 *
+	 * @see WP_List_Util::sort()
+	 *
+	 * @param object|array $a One object to compare.
+	 * @param object|array $b The other object to compare.
+	 * @return int 0 if both objects equal. -1 if second object should come first, 1 otherwise.
+	 */
+	private function sort_callback( $a, $b ) {
+		if ( empty( $this->orderby ) ) {
+			return 0;
+		}
+
+		$a = (array) $a;
+		$b = (array) $b;
+
+		foreach ( $this->orderby as $field => $direction ) {
+			if ( ! isset( $a[ $field ] ) || ! isset( $b[ $field ] ) ) {
+				continue;
+			}
+
+			if ( $a[ $field ] == $b[ $field ] ) {
+				continue;
+			}
+
+			$results = 'DESC' === $direction ? array( 1, -1 ) : array( -1, 1 );
+
+			if ( is_numeric( $a[ $field ] ) && is_numeric( $b[ $field ] ) ) {
+				return ( $a[ $field ] < $b[ $field ] ) ? $results[0] : $results[1];
+			}
+
+			return 0 > strcmp( $a[ $field ], $b[ $field ] ) ? $results[0] : $results[1];
+		}
+
+		return 0;
+	}
+}
diff --git src/wp-includes/functions.php src/wp-includes/functions.php
index fa7e725..020f69a 100644
--- src/wp-includes/functions.php
+++ src/wp-includes/functions.php
@@ -3444,6 +3444,7 @@ function wp_is_numeric_array( $data ) {
  * Filters a list of objects, based on a set of key => value arguments.
  *
  * @since 3.0.0
+ * @since 4.7.0 Uses WP_List_Util class.
  *
  * @param array       $list     An array of objects to filter
  * @param array       $args     Optional. An array of key => value arguments to match
@@ -3457,21 +3458,26 @@ function wp_is_numeric_array( $data ) {
  * @return array A list of objects or object fields.
  */
 function wp_filter_object_list( $list, $args = array(), $operator = 'and', $field = false ) {
-	if ( ! is_array( $list ) )
+	if ( ! is_array( $list ) ) {
 		return array();
+	}
+
+	$util = new WP_List_Util( $list );
 
-	$list = wp_list_filter( $list, $args, $operator );
+	$util->filter( $args, $operator );
 
-	if ( $field )
-		$list = wp_list_pluck( $list, $field );
+	if ( $field ) {
+		$util->pluck( $field );
+	}
 
-	return $list;
+	return $util->get_output();
 }
 
 /**
  * Filters a list of objects, based on a set of key => value arguments.
  *
  * @since 3.1.0
+ * @since 4.7.0 Uses WP_List_Util class.
  *
  * @param array  $list     An array of objects to filter.
  * @param array  $args     Optional. An array of key => value arguments to match
@@ -3483,33 +3489,12 @@ function wp_filter_object_list( $list, $args = array(), $operator = 'and', $fiel
  * @return array Array of found values.
  */
 function wp_list_filter( $list, $args = array(), $operator = 'AND' ) {
-	if ( ! is_array( $list ) )
+	if ( ! is_array( $list ) ) {
 		return array();
-
-	if ( empty( $args ) )
-		return $list;
-
-	$operator = strtoupper( $operator );
-	$count = count( $args );
-	$filtered = array();
-
-	foreach ( $list as $key => $obj ) {
-		$to_match = (array) $obj;
-
-		$matched = 0;
-		foreach ( $args as $m_key => $m_value ) {
-			if ( array_key_exists( $m_key, $to_match ) && $m_value == $to_match[ $m_key ] )
-				$matched++;
-		}
-
-		if ( ( 'AND' == $operator && $matched == $count )
-		  || ( 'OR' == $operator && $matched > 0 )
-		  || ( 'NOT' == $operator && 0 == $matched ) ) {
-			$filtered[$key] = $obj;
-		}
 	}
 
-	return $filtered;
+	$util = new WP_List_Util( $list );
+	return $util->filter( $args, $operator );
 }
 
 /**
@@ -3520,6 +3505,7 @@ function wp_list_filter( $list, $args = array(), $operator = 'AND' ) {
  *
  * @since 3.1.0
  * @since 4.0.0 $index_key parameter added.
+ * @since 4.7.0 Uses WP_List_Util class.
  *
  * @param array      $list      List of objects or arrays
  * @param int|string $field     Field from the object to place instead of the entire object
@@ -3530,43 +3516,29 @@ function wp_list_filter( $list, $args = array(), $operator = 'AND' ) {
  *               `$list` will be preserved in the results.
  */
 function wp_list_pluck( $list, $field, $index_key = null ) {
-	if ( ! $index_key ) {
-		/*
-		 * This is simple. Could at some point wrap array_column()
-		 * if we knew we had an array of arrays.
-		 */
-		foreach ( $list as $key => $value ) {
-			if ( is_object( $value ) ) {
-				$list[ $key ] = $value->$field;
-			} else {
-				$list[ $key ] = $value[ $field ];
-			}
-		}
-		return $list;
-	}
+	$util = new WP_List_Util( $list );
+	return $util->pluck( $field, $index_key );
+}
 
-	/*
-	 * When index_key is not set for a particular item, push the value
-	 * to the end of the stack. This is how array_column() behaves.
-	 */
-	$newlist = array();
-	foreach ( $list as $value ) {
-		if ( is_object( $value ) ) {
-			if ( isset( $value->$index_key ) ) {
-				$newlist[ $value->$index_key ] = $value->$field;
-			} else {
-				$newlist[] = $value->$field;
-			}
-		} else {
-			if ( isset( $value[ $index_key ] ) ) {
-				$newlist[ $value[ $index_key ] ] = $value[ $field ];
-			} else {
-				$newlist[] = $value[ $field ];
-			}
-		}
+/**
+ * Sorts a list of objects, based on one or more orderby arguments.
+ *
+ * @since 4.7.0
+ *
+ * @param array        $list    An array of objects to filter.
+ * @param string|array $orderby Optional. Either the field name to order by or an array
+ *                              of multiple orderby fields as $orderby => $order.
+ * @param string       $order   Optional. Either 'ASC' or 'DESC'. Only used if $orderby
+ *                              is a string.
+ * @return array The sorted array.
+ */
+function wp_list_sort( $list, $orderby = array(), $order = 'ASC' ) {
+	if ( ! is_array( $list ) ) {
+		return array();
 	}
 
-	return $newlist;
+	$util = new WP_List_Util( $list );
+	return $util->sort( $orderby, $order );
 }
 
 /**
diff --git src/wp-settings.php src/wp-settings.php
index 4a03e0a..a3bdfd7 100644
--- src/wp-settings.php
+++ src/wp-settings.php
@@ -91,6 +91,7 @@ wp_set_lang_dir();
 
 // Load early WordPress files.
 require( ABSPATH . WPINC . '/compat.php' );
+require( ABSPATH . WPINC . '/class-wp-list-util.php' );
 require( ABSPATH . WPINC . '/functions.php' );
 require( ABSPATH . WPINC . '/class-wp.php' );
 require( ABSPATH . WPINC . '/class-wp-error.php' );
diff --git tests/phpunit/tests/functions/wpListUtil.php tests/phpunit/tests/functions/wpListUtil.php
new file mode 100644
index 0000000..ca20b06
--- /dev/null
+++ tests/phpunit/tests/functions/wpListUtil.php
@@ -0,0 +1,341 @@
+<?php
+
+/**
+ * @group functions.php
+ */
+class Tests_WP_List_Util extends WP_UnitTestCase {
+	public function data_test_wp_list_pluck() {
+		return array(
+			'arrays'                         => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz' ),
+					array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum' ),
+					array( 'foo' => 'baz' ),
+				),
+				'foo',
+				null,
+				array( 'bar', 'foo', 'baz' ),
+			),
+			'arrays with index key'          => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+				),
+				'foo',
+				'key',
+				array( 'foo' => 'bar', 'bar' => 'foo', 'value' => 'baz' ),
+			),
+			'arrays with index key missing'  => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz' ),
+					array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+				),
+				'foo',
+				'key',
+				array( 'bar' => 'foo', 'value' => 'baz', 'bar' ),
+			),
+			'objects'                        => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum' ),
+					(object) array( 'foo' => 'baz' ),
+				),
+				'foo',
+				null,
+				array( 'bar', 'foo', 'baz' ),
+			),
+			'objects with index key'         => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value' ),
+				),
+				'foo',
+				'key',
+				array( 'foo' => 'bar', 'bar' => 'foo', 'value' => 'baz' ),
+			),
+			'objects with index key missing' => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value' ),
+				),
+				'foo',
+				'key',
+				array( 'bar' => 'foo', 'value' => 'baz', 'bar' ),
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider data_test_wp_list_pluck
+	 *
+	 * @param array      $list      List of objects or arrays.
+	 * @param int|string $field     Field from the object to place instead of the entire object
+	 * @param int|string $index_key Field from the object to use as keys for the new array.
+	 * @param array      $expected  Expected result.
+	 */
+	public function test_wp_list_pluck( $list, $field, $index_key, $expected ) {
+		$this->assertEqualSetsWithIndex( $expected, wp_list_pluck( $list, $field, $index_key ) );
+	}
+
+	public function data_test_wp_list_filter() {
+		return array(
+			'string instead of array'  => array(
+				'foo',
+				array(),
+				'AND',
+				array(),
+			),
+			'object instead of array'  => array(
+				(object) array( 'foo' ),
+				array(),
+				'AND',
+				array(),
+			),
+			'empty args'               => array(
+				array( 'foo', 'bar' ),
+				array(),
+				'AND',
+				array( 'foo', 'bar' ),
+			),
+			'invalid operator'         => array(
+				array(
+					(object) array( 'foo' => 'bar' ),
+					(object) array( 'foo' => 'baz' ),
+				),
+				array( 'foo' => 'bar' ),
+				'XOR',
+				array(),
+			),
+			'single argument to match' => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value' ),
+					(object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'foo' => 'bar' ),
+				'AND',
+				array(
+					0 => (object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					3 => (object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+			),
+			'all must match'           => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value', 'bar' => 'baz' ),
+					(object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'foo' => 'bar', 'bar' => 'baz' ),
+				'AND',
+				array(
+					0 => (object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+				),
+			),
+			'any must match'           => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value', 'bar' => 'baz' ),
+					(object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'key' => 'value', 'bar' => 'baz' ),
+				'OR',
+				array(
+					0 => (object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					2 => (object) array( 'foo' => 'baz', 'key' => 'value', 'bar' => 'baz' ),
+					3 => (object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+			),
+			'none must match'          => array(
+				array(
+					(object) array( 'foo' => 'bar', 'bar' => 'baz', 'abc' => 'xyz', 'key' => 'foo' ),
+					(object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					(object) array( 'foo' => 'baz', 'key' => 'value' ),
+					(object) array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'key' => 'value', 'bar' => 'baz' ),
+				'NOT',
+				array(
+					1 => (object) array( 'foo' => 'foo', '123' => '456', 'lorem' => 'ipsum', 'key' => 'bar' ),
+				),
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider data_test_wp_list_filter
+	 *
+	 * @param array  $list     An array of objects to filter.
+	 * @param array  $args     An array of key => value arguments to match
+	 *                         against each object.
+	 * @param string $operator The logical operation to perform.
+	 * @param array  $expected Expected result.
+	 */
+	public function test_wp_list_filter( $list, $args, $operator, $expected ) {
+		$this->assertEqualSetsWithIndex( $expected, wp_list_filter( $list, $args, $operator ) );
+	}
+
+	public function data_test_wp_list_sort() {
+		return array(
+			'single orderby ascending'        => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				'foo',
+				'ASC',
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+				),
+			),
+			'single orderby descending'       => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				'foo',
+				'DESC',
+				array(
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+			),
+			'single orderby array ascending'  => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'foo' => 'ASC' ),
+				'IGNORED',
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+				),
+			),
+			'single orderby array descending' => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'foo' => 'DESC' ),
+				'IGNORED',
+				array(
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'baz', 'key' => 'value' ),
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+			),
+			'multiple orderby ascending'      => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'key' => 'ASC', 'foo' => 'ASC' ),
+				'IGNORED',
+				array(
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+			),
+			'multiple orderby descending'     => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'key' => 'DESC', 'foo' => 'DESC' ),
+				'IGNORED',
+				array(
+					array( 'foo' => 'bar', 'key' => 'value' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+				),
+			),
+			'multiple orderby mixed'          => array(
+				array(
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'key' => 'value' ),
+				),
+				array( 'key' => 'DESC', 'foo' => 'ASC' ),
+				'IGNORED',
+				array(
+					array( 'foo' => 'bar', 'key' => 'value' ),
+					array( 'foo' => 'baz', 'key' => 'key' ),
+					array( 'foo' => 'foo', 'key' => 'key' ),
+					array( 'foo' => 'bar', 'bar' => 'baz', 'key' => 'foo' ),
+					array( 'foo' => 'foo', 'lorem' => 'ipsum', 'key' => 'bar' ),
+				),
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider data_test_wp_list_sort
+	 *
+	 * @param string|array $orderby Either the field name to order by or an array
+	 *                              of multiple orderby fields as $orderby => $order.
+	 * @param string       $order   Either 'ASC' or 'DESC'.
+	 */
+	public function test_wp_list_sort( $list, $orderby, $order, $expected ) {
+		$this->assertEquals( $expected, wp_list_sort( $list, $orderby, $order ) );
+	}
+
+	public function test_wp_list_util_get_input() {
+		$input = array( 'foo', 'bar' );
+		$util  = new WP_List_Util( $input );
+
+		$this->assertEqualSets( $input, $util->get_input() );
+	}
+
+	public function test_wp_list_util_get_output_immediately() {
+		$input = array( 'foo', 'bar' );
+		$util  = new WP_List_Util( $input );
+
+		$this->assertEqualSets( $input, $util->get_output() );
+	}
+
+	public function test_wp_list_util_get_output() {
+		$expected = array( (object) array( 'foo' => 'bar', 'bar' => 'baz' ) );
+
+		$util   = new WP_List_Util( array( (object) array( 'foo' => 'bar', 'bar' => 'baz' ), (object) array( 'bar' => 'baz' ) ) );
+		$actual = $util->filter( array( 'foo' => 'bar' ) );
+
+		$this->assertEqualSets( $expected, $actual );
+		$this->assertEqualSets( $expected, $util->get_output() );
+	}
+}