diff --git tests/phpunit/tests/admin/includesTemplate.php tests/phpunit/tests/admin/includesTemplate.php
index c0bc3b8..d0bf20c 100644
--- tests/phpunit/tests/admin/includesTemplate.php
+++ tests/phpunit/tests/admin/includesTemplate.php
@@ -108,4 +108,41 @@ class Tests_Admin_includesTemplate extends WP_UnitTestCase {
 		$this->assertFalse( $wp_meta_boxes['attachment']['advanced']['default']['testbox1'] );
 	}
 
+	/**
+	 * @ticket 42791
+	 */
+	public function test_wp_add_dashboard_widget() {
+		global $wp_meta_boxes;
+
+		set_current_screen( 'dashboard' );
+
+		if ( ! function_exists( 'wp_add_dashboard_widget' ) ) {
+			require_once ABSPATH . 'wp-admin/includes/dashboard.php';
+		}
+
+		// Some hardcoded defaults for core widgets
+		wp_add_dashboard_widget( 'dashboard_quick_press', 'Quick', '__return_false' );
+		wp_add_dashboard_widget( 'dashboard_browser_nag', 'Nag', '__return_false' );
+
+		$this->assertArrayHasKey( 'dashboard_quick_press', $wp_meta_boxes['dashboard']['side']['core'] );
+		$this->assertArrayHasKey( 'dashboard_browser_nag', $wp_meta_boxes['dashboard']['normal']['high'] );
+
+		// Location and priority defaults
+		wp_add_dashboard_widget( 'dashboard1', 'Widget 1', '__return_false', null, null, 'foo' );
+		wp_add_dashboard_widget( 'dashboard2', 'Widget 2', '__return_false', null, null, null, 'bar' );
+
+		$this->assertArrayHasKey( 'dashboard1', $wp_meta_boxes['dashboard']['foo']['core'] );
+		$this->assertArrayHasKey( 'dashboard2', $wp_meta_boxes['dashboard']['normal']['bar'] );
+
+		// Cleanup
+		remove_meta_box( 'dashboard_quick_press', 'dashboard', 'side' );
+		remove_meta_box( 'dashboard_browser_nag', 'dashboard', 'normal' );
+		remove_meta_box( 'dashboard1', 'dashboard', 'foo' );
+
+		// This doesn't actually get removed due to the invalid priority
+		remove_meta_box( 'dashboard2', 'dashboard', 'normal' );
+
+		set_current_screen( 'front' );
+	}
+
 }