Method update

packages/core/test/render3/view_fixture.ts:193–203

* Invokes an update block function, which can either be provided during * the `ViewFixture` initialization or as an argument. * * @param updateFn An update block function to invoke.

(updateFn?: () => void)

   * @param updateFn An update block function to invoke.
   */
  update(updateFn?: () => void) {
    updateFn ||= this.updateFn;
    if (!updateFn) {
      throw new Error(
        'The `ViewFixture.update` was invoked, but there was no `update` function ' +
          'provided during the `ViewFixture` instantiation or specified as an argument ' +
          'in this call.',
      );
    }
    refreshView(this.tView, this.lView, updateFn, this.context);
  }

  /**
   * If you use `ViewFixture` and `enter()`, please add `afterEach(ViewFixture.cleanup);` to ensure