Add testing #522
Description
There's currently a very limited set of tests for e2e pptx generation. Since these tests are a relatively nice way of ensuring that library functionality does what's expected, it would be nice to have many more of them. See https://github.com/wyozi/react-pptx/blob/master/src/index.spec.tsx#L205 for an example
Some test ideas:
- Test that every node type appears in the slide (Text, Shape etc)
- Test master slides
- Test percentage dimensions mapping to absolute values
- Test pptx layouts
- Test color mapping to .pptx colors