set-up threejs testing

[Bryanz2019]

Initial Issue: Cannot find Module 'three/addons/exporters/GLTFExporter.js'
Possible Cause?: facebook/create-react-app#2537 or library path issue
Attempt Solution (failed): customize jest.config with transformIgnorePatterns
Final Solution: import gltfexporter from a different source

Initial Issue: ResizeObserver is not supported in this browser out of the box
HandleBlur prop cannot be recognized on a DOM element
Possible Cause?: https://github.com/pmndrs/react-use-measure#resize-observer-polyfills
ZeeCoder/use-resize-observer#40
Attempt Solution (failed): mocking ResizeObserver with jest
Temporary Solution: Avoid using render for now
Test with Enzyme's shallow copy to isolate the component

Initial Issue: model rendered with missing context
Attempt Solution (failed): pass in context from App; modify undefined context
Final Solution: modify the structure of Model.js to accept the default context

[Bryanz2019]

The rest of the testing on the mesh object could be done by passing in different prop value

[christinetu15]

looks good! don't forget to update the testing.md doc to say you used enzyme. thanks!