17: Add solutions for section "tests".

Created by  Aaw9nJhsNmfzFih9mKyNw9mV8CgERXJkRa1kK1Kx3LQH  on August 7, 2021
4JIQ62DMDBZ6TWTIDZL7HF2OP47QHXJLZ74TON5WC63IGLFKQORAC
In channels
main
Change contents