Relying on --data-dir can be problematic.

[0xFFFC0000]

In functional_tests we define --data-dir for the daemon but, the daemon will read the default --config-file too. If you have anything in your default config file that would interfere with tests, that means tests are not going to run correctly.

E.g. you can run the mining test in functional_tests with:

/usr/bin/python3 /home/0xfffc/developments/monero/tests/functional_tests/functional_tests_rpc.py /usr/bin/python3 /home/0xfffc/developments/monero/tests/functional_tests /home/0xfffc/developments/monero/build mining

these are the commands we are running for the mining test in functional_tests:

/home/0xfffc/developments/monero/build/bin/monerod --regtest --fixed-difficulty 10 --no-igd --p2p-bind-port 18280 --rpc-bind-port 18180 --zmq-rpc-bind-port 18380 --zmq-pub tcp://127.0.0.1:18480 --non-interactive --disable-dns-checkpoints --check-updates disabled --rpc-ssl disabled --data-dir /home/0xfffc/developments/monero/build/functional-tests-directory/monerod0 --log-level 1 --offline


/home/0xfffc/developments/monero/build/bin/monerod --regtest --fixed-difficulty 10 --no-igd --p2p-bind-port 18281 --rpc-bind-port 18181 --zmq-rpc-bind-port 18381 --zmq-pub tcp://127.0.0.1:18481 --non-interactive --disable-dns-checkpoints --check-updates disabled --rpc-ssl disabled --data-dir /home/0xfffc/developments/monero/build/functional-tests-directory/monerod1 --log-level 1 --rpc-payment-address 44SKxxLQw929wRF6BA9paQ1EWFshNnKhXM3qz6Mo3JGDE2YG3xyzVutMStEicxbQGRfrYvAAYxH6Fe8rnD56EaNwUiqhcwR --rpc-payment-difficulty 10 --rpc-payment-credits 5000 --offline


/home/0xfffc/developments/monero/build/bin/monerod --regtest --fixed-difficulty 10 --no-igd --p2p-bind-port 18282 --rpc-bind-port 18182 --zmq-rpc-bind-port 18382 --zmq-pub tcp://127.0.0.1:18482 --non-interactive --disable-dns-checkpoints --check-updates disabled --rpc-ssl disabled --data-dir /home/0xfffc/developments/monero/build/functional-tests-directory/monerod2 --log-level 1 --add-exclusive-node 127.0.0.1:18283


/home/0xfffc/developments/monero/build/bin/monerod --regtest --fixed-difficulty 10 --no-igd --p2p-bind-port 18283 --rpc-bind-port 18183 --zmq-rpc-bind-port 18383 --zmq-pub tcp://127.0.0.1:18483 --non-interactive --disable-dns-checkpoints --check-updates disabled --rpc-ssl disabled --data-dir /home/0xfffc/developments/monero/build/functional-tests-directory/monerod3 --log-level 1 --add-exclusive-node 127.0.0.1:18282


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18090 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --daemon-port 18180


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18091 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --daemon-port 18180


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18092 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --daemon-port 18180


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18093 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --daemon-port 18180


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18094 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --daemon-port 18182


/home/0xfffc/developments/monero/build/bin/monero-wallet-rpc --wallet-dir /home/0xfffc/developments/monero/build/functional-tests-directory --rpc-bind-port 18095 --disable-rpc-login --rpc-ssl disabled --daemon-ssl disabled --log-level 1 --allow-mismatched-daemon-version --offline

[hyc]

Would be a good idea to have a --no-config-file option to prevent that from being read while running tests.
Or, have the test suite create its own config file and specify that.