addPartialStream(type, func) {
    const ContentType = shaka.util.ManifestParserUtils.ContentType;

    const stream = new shaka.test.ManifestGenerator.Stream(
        this.manifest_, /* isPartial= */ true, null, type);
    if (func) {
      func(stream);
    }

    const streamObj = /** @type {shaka.extern.Stream} */ (
      jasmine.objectContaining(stream.build_()));
    if (type == ContentType.AUDIO) {
      this.audio = streamObj;
    } else {
      goog.asserts.assert(
          type == ContentType.VIDEO, 'Must be audio or video');
      this.video = streamObj;
    }
  }
Adds a "partial" stream which, when used with jasmine, will only compare
the properties that were explicitly given to it.  All other properties will
be ignored.

@param {shaka.util.ManifestParserUtils.ContentType} type
@param {function(!shaka.test.ManifestGenerator.Stream)=} func