Unit tests missing

[laisolizq]

It is necessary to add unit tests for all functionalities and endpoints.

[jeffprestes]

Thanks @laisolizq .
@marioidival is doing a good job and the decision to left some items such as unit tests for later was mine.
We're prioritizing to test and create some functionalities first and later if we decided to stay with Price Updater as one more full Hermez/Iden3 software for sure we're going to add them and make other adjustments.