Running tests is easy:
make -j
This command will format all code as it should be, will run all necessary tests and checks. Just like it is done during CI for a PR.
To run integration tests one must specify an access token in an environment variable:
export SHIPANDCO_ACCESS_TOKEN=...
Then it is recommended to run tests in a debugging mode:
vendor/bin/phpunit --group=integration --debug
This command will show requestes and responses as they happen.