Switch to snforge for testing #390
Description
scarb cairo-test is being deprecated
also, snforge executes tests much faster
Resources:
- https://foundry-rs.github.io/starknet-foundry/getting-started/installation.html
- https://foundry-rs.github.io/starknet-foundry/getting-started/first-steps.html#using-snforge-with-existing-scarb-projects
Related exercism/cairo-test-runner#41