cellxgene/dev_docs/developer_guidelines.md

Developer guidelines

Requirements

• npm
• Python 3.6+
• Chrome

See dev section of README

All instructions are expected to be run from the top level cellxgene directory unless otherwise specified.

Environment

For all make commands, common.mk automatically checks whether required environment variables are set and, if they are not set, assigns them default values from environment.default.

You can set these environment variables manually with the export shell command, as in export JEST_ENV=debug.

Running test suite

Client and server tests run on Travis CI for every push, PR, and commit to master on github. End to end tests run nightly on master only.

Unit tests

Steps to run the all unit tests:

1. Start in the project root directory
2. make dev-env
3. make unit-test

To run unit tests for the client code only:

1. Start in the project root directory
2. cd client
3. make unit-test

End to end tests

To run E2E tests, run cd client and make smoke-test

The JEST_ENV environment variable enables the following E2E test options:

• dev - opens chromimum, runs tests with minimal slowdown, close on exit.
• debug - opens chromium, runs tests with 100ms slowdown, dev tools open, chrome stays open on exit.
• prod - run headless with no slowdown, chromium will not open.

Run end to end tests interactively during development

1. cellxgene should be installed as specified in client dev
2. Follow launch instructions for client dev with dataset example-dataset/pbmc3k
3. Run npm run e2e or make e2e from the client directory
4. To debug a failing test export JEST_ENV='debug' and re-run.

To run end to end tests exactly as they will be run on CI use the following command:

JEST_ENV=prod make pydist install-dist dev-env smoke-test

Server dev

Install

• Build the client and put static files in place: make build-for-server-dev
• Install from local files: make install-dev

Launch

• cellxgene launch [options] <datafile>

Reloading

If you install cellxgene using make install-dev the server will be restarted every time you make changes on the server code. If changes affects the client, the browser must be reloaded.

Linter

We use flake8 to lint python and black for auto-formatting.

To auto-format code run make fmt. To run lint checks on the code run make lint.

Test

If you would like to run the server tests individually, follow the steps below

1. Install development requirements make dev-env
2. Run make unit-test in the server directory or make unit-test-server in the root directory.

Tips

• Install in a virtualenv
• May need to rebuild/reinstall when you make client changes

Client dev

Install

1. Install prereqs for client: make dev-env
2. Install cellxgene server: make install-dev Caveat: this will not build the production client package - you must use the server install instructions above to serve web assets.

Launch

To launch with hot reloading you need to launch the server and the client separately. Node's hot reloading starts the client on its own node server and auto-refreshes when changes are made.

1. Launch server (the client relies on the REST API being available): cellxgene launch [options] <datafile>
2. Launch client: in client/ directory run npm run start
3. Client will be served on localhost:3000

Build

To build only the client: make build-client

Linter

We use eslint to lint the code and prettier as our code formatter.

Test

If you would like to run the client tests individually, follow the steps below in the client directory

1. For unit tests run npm run unit-test or make unit-test
2. For the smoke test run npm run smoke-test or make smoke-test

Tips

• You can also install/launch the server side code from npm scrips (requires python3.6 with virtualenv) in client/ directory run npm run backend-dev