  const stackFrameView = document.createElement('tr-ui-a-stack-frame');
    stackFrameView.stackFrame = fA;
    this.addHTMLOutput(stackFrameView);
  });

  test('clearingStackFrame', function() {
    const model = new tr.Model();
    const fA = tr.c.TestUtils.newStackTrace(model, ['a1', 'a2', 'a3']);

    const stackFrameView = document.createElement('tr-ui-a-stack-frame');
    stackFrameView.stackFrame = fA;
    stackFrameView.stackFrame = undefined;

    assert.isUndefined(stackFrameView.stackFrame);
   