public function test_locations_with_same_slug() {
    $this->register_nav_menu_locations( array( 'primary', 'secondary' ) );
    $prev_theme_nav_menu_locations = array(
      'primary'   => 1,
      'secondary' => 2,
    );

    $old_next_theme_nav_menu_locations = array(); // It was not active before.
    $new_next_theme_nav_menu_locations = wp_map_nav_menu_locations( $old_next_theme_nav_menu_locations, $prev_theme_nav_menu_locations );

    $expected_nav_menu_locations = $prev_theme_nav_menu_locations;
    $this->assertSame( $expected_nav_menu_locations, $new_next_theme_nav_menu_locations );
  }