Parallelization of independent test commands

My tests consist in a series of independent test commands:

test:
    override:
        - eslint --ext=.js --ext=.jsx frontend
        - karma start frontend/config/karma.circleci.js --single-run
        - flake8
        - isort --check-only --diff --recursive
        - pytest -m 'not e2e' -p no:sugar --cov=backend --junit-xml=$CIRCLE_TEST_REPORTS/backend/junit.xml
        - pytest -m 'e2e and not no_ci' -p no:sugar --junit-xml=$CIRCLE_TEST_REPORTS/end-to-end/junit.xml --splinter-webdriver=chrome

The easiest way to parallelize them would be to have each container run some of these commands, until they’ve all been run.

For example container 0 would run:

        - eslint --ext=.js --ext=.jsx frontend
        - flake8
        - pytest -m 'not e2e' -p no:sugar --cov=backend --junit-xml=$CIRCLE_TEST_REPORTS/backend/junit.xml

And container 1 would run:

        - karma start frontend/config/karma.circleci.js --single-run
        - isort --check-only --diff --recursive
        - pytest -m 'e2e and not no_ci' -p no:sugar --junit-xml=$CIRCLE_TEST_REPORTS/end-to-end/junit.xml --splinter-webdriver=chrome

Is this possible? I couldn’t find a reference to that behavior in the docs. I suppose it may be difficult because containers run independently and there’s no mechanism for distributing tests?

I can work around this with a bash script as described in the docs. That feels a bit messy, though.

Note that in my case, pytest’s start-up time is large (due to Django’s migrations, mostly), so running it multiple times on different files won’t file.

You will need to use if statements;

if [[ $CIRCLE_NODE_INDEX = 0 ]]; then
        eslint --ext=.js --ext=.jsx frontend \
        && flake8 \
        && pytest -m 'not e2e' -p no:sugar --cov=backend --junit-xml=$CIRCLE_TEST_REPORTS/backend/junit.xml;
fi