Check out repo in install test so we can compute cache keys
Check out repo in install test so we can compute cache keys

ipython/ipywidgets,ipython/ipywidgets,jupyter-widgets/ipywidgets,jupyter-widgets/ipywidgets,ipython/ipywidgets,ipython/ipywidgets,jupyter-widgets/ipywidgets,jupyter-widgets/ipywidgets,ipython/ipywidgets