function makeAVVariant(height, language, channels = 2, roles = []) {
    const variant = jasmine.objectContaining({
      language,
      audio: jasmine.objectContaining({
        language,
        roles,
        channelsCount: channels,
      }),
      video: jasmine.objectContaining({
        height,
      }),
    });
    return /** @type {shaka.extern.Variant} */(/** @type {?} */(variant));
  }
@param {number} height
@param {string} language
@param {number=} channels
@param {!Array<string>=} roles
@return {shaka.extern.Variant}