Fix failure seen on running `npm test`

[punamdahiya]

Scope of this bug is to fix test run that's failing most probably due to esmifying of modules

[aminomancer]

I think it's because the test script uses ts-node but we use parcel to build the project, not tsc. The script stopped working recently, after we stopped using tsc. So probably it needs parcel watch instead of ts-node register. I filed #298 as a followup to add working unit tests (the existing tests are also super old so they don't cover much).