@@ -0,0 +1,132 @@
+<?php
+
+/**
+ * Tests for author_can().
+ *
+ * @group user
+ * @group capabilities
+ *
+ * @covers ::author_can
+ */
+class Tests_User_AuthorCan extends WP_UnitTestCase {
+
+	/**
+	 * Editor user ID.
+	 *
+	 * @var int
+	 */
+	protected static $editor_id;
+
+	/**
+	 * Contributor user ID.
+	 *
+	 * @var int
+	 */
+	protected static $contributor_id;
+
+	/**
+	 * Published post by the editor.
+	 *
+	 * @var WP_Post
+	 */
+	protected static $editor_post;
+
+	/**
+	 * Draft post by the contributor.
+	 *
+	 * @var WP_Post
+	 */
+	protected static $contributor_draft;
+
+	/**
+	 * Published post by the contributor.
+	 *
+	 * @var WP_Post
+	 */
+	protected static $contributor_published;
+
+	public static function wpSetUpBeforeClass( WP_UnitTest_Factory $factory ) {
+		self::$editor_id      = $factory->user->create( array( 'role' => 'editor' ) );
+		self::$contributor_id = $factory->user->create( array( 'role' => 'contributor' ) );
+
+		self::$editor_post           = $factory->post->create_and_get( array( 'post_author' => self::$editor_id ) );
+		self::$contributor_draft     = $factory->post->create_and_get(
+			array(
+				'post_author' => self::$contributor_id,
+				'post_status' => 'draft',
+			)
+		);
+		self::$contributor_published = $factory->post->create_and_get( array( 'post_author' => self::$contributor_id ) );
+	}
+
+	/**
+	 * Tests that the capability is checked against the post's author.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_checks_capability_of_post_author() {
+		$this->assertTrue( author_can( self::$editor_post, 'edit_others_posts' ), 'An editor should be able to edit others\' posts.' );
+		$this->assertFalse( author_can( self::$contributor_draft, 'edit_others_posts' ), 'A contributor should not be able to edit others\' posts.' );
+	}
+
+	/**
+	 * Tests that a post ID is accepted as well as a post object.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_accepts_post_id() {
+		$this->assertTrue( author_can( self::$editor_post->ID, 'publish_posts' ), 'The editor\'s post ID should resolve to the editor.' );
+		$this->assertFalse( author_can( self::$contributor_draft->ID, 'publish_posts' ), 'The contributor\'s post ID should resolve to the contributor.' );
+	}
+
+	/**
+	 * Tests that the result does not depend on the current user.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_ignores_current_user() {
+		wp_set_current_user( self::factory()->user->create( array( 'role' => 'administrator' ) ) );
+
+		$this->assertFalse( author_can( self::$contributor_draft, 'edit_others_posts' ) );
+	}
+
+	/**
+	 * Tests that extra arguments are passed on, so meta capabilities are checked for the given object.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_passes_extra_arguments_for_meta_capabilities() {
+		$this->assertTrue(
+			author_can( self::$contributor_draft, 'edit_post', self::$contributor_draft->ID ),
+			'A contributor should be able to edit their own draft.'
+		);
+		$this->assertFalse(
+			author_can( self::$contributor_draft, 'edit_post', self::$contributor_published->ID ),
+			'A contributor should not be able to edit their own published post.'
+		);
+		$this->assertFalse(
+			author_can( self::$contributor_draft, 'edit_post', self::$editor_post->ID ),
+			'A contributor should not be able to edit another user\'s post.'
+		);
+	}
+
+	/**
+	 * Tests that false is returned for a post that does not exist.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_returns_false_for_missing_post() {
+		$this->assertFalse( author_can( PHP_INT_MAX, 'read' ) );
+	}
+
+	/**
+	 * Tests that false is returned when the post's author does not exist.
+	 *
+	 * @ticket 65819
+	 */
+	public function test_returns_false_for_missing_author() {
+		$post = self::factory()->post->create_and_get( array( 'post_author' => PHP_INT_MAX ) );
+
+		$this->assertFalse( author_can( $post, 'read' ) );
+	}
+}