PingPong and Sample contract examples (DON'T MERGE)

[bogdan-manole]

Usage/Run tests

cabal run convex-coin-selection-test -- -p 'ha scripts' 

Output

unit tests
  ha scripts
    spend an output succeeds:         OK (0.09s)
    spend an output fails:            OK
    ping-pong
      Ping and Pong should succeed:   OK
      Pong and Ping should succeed:   OK
      Ping and Ping should fail:      OK
      Pong and Pong should fail:      OK
      Stop after Ping should succeed: OK
      Stop after Pong should succeed: OK
      Stop after Stop should fail:    OK
      Ping after Stop should fail:    OK
      Pong after Stop should fail:    OK