Side by side tests

[SebastianStehle]

Hi,

I have some components where I am building new implementations. One is based on SVG and the other on WebGL. They are very complex and I would like to ensure that they are the same.

Ideallly

1. I only write the tests once but use some kind parameters to inject some behavior into them:
2. I have a side by side view to compare the results.

Is this possible somehow? e.g. one of them?