* add some unit tests for estimateGas
Also add some test environment setup, Closes#323
test estimateGas of erc20 token transfer
fix failed test case
the trick is to keep a clean transient store, by doing a commit
put artifacts to external file
* fix test failure
Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>
