Developer Guide

This developer guide aims to get you started with developing LNT. At the moment, a lot of detailed info is missing, but hopefully this will get you started.

Installation

See Quickstart Guide for setting up an installation. Pass -e to pip when installing the package to install it in “editable” mode.

Running LNT’s Regression Tests

LNT has a growing body of regression tests that makes it easier to improve LNT without accidentally breaking existing functionality. Just like when developing most other LLVM sub-projects, you should consider adding regression tests for every feature you add or every bug you fix. The regression tests must pass at all times, therefore you should run the regression tests as part of your development work-flow, just like you do when developing on other LLVM sub-projects.

The LNT regression tests make use of lit and other tools like [filecheck](https://github.com/AntonLydike/filecheck). To run the tests, we recomment using tox in a virtual environment:

python3 -m venv .venv
source .venv/bin/activate
pip install tox
tox

You can also run individual unit tests with lit directly:

pip install lit
lit -sv ./tests

However, that requires manually setting up the testing environment (filecheck, etc).

For simple changes, adding a regression test and making sure all regression tests pass, is often a good enough testing approach. For some changes, the existing regression tests aren’t good enough at the moment, and manual testing will be needed.

Optional Tests

Some tests require additional tools to be installed and are not enabled by default. You can enable them by passing additional flags to lit:

-Dpostgres=1

Enable postgres database support testing. This requires at least postgres version 9.2 and the initdb and postgres binaries in your path. Note that you do not need to setup an actual server, the tests will create temporary instances on demand.

-Dmysql=1

Enable mysql database support testing. This requires MySQL-python to be installed and expects the mysqld and mysqladmin binaries in your path. Note that you do not need to setup an actual server, the tests will create temporary instances on demand.

-Dtidylib=1

Check generated html pages for errors using tidy-html5. This requires pytidylib and tidy-html5 to be installed.

-Dcheck-coverage=1

Enable coverage.py reporting, assuming the coverage module has been installed and sitecustomize.py in the virtualenv has been modified appropriately.

Example:

lit -sv -Dpostgres=1 -Dmysql=1 -Dtidylib=1 ./tests