Use tdd in all cases to be more consisstend.
Also since last year we can use chai with rollup directly, so
do that everywhere instead of relying on karma-chai injecting
it in to the global scope.

I couldn't find any breaking changes affecting us

We couldn't do this until now because we referenced them by a relative path with npm.
But now that we reference them by name and yarn handles the linking we can
specify them as normal dependencies.

From what I remember this got added in v12

Fixes #5

They are not published yet

No longer needed