env.md

Exposed environment variables

git test exports the following environment variables which can for instance be used if test are run through scripts.

• GIT_TEST_VERBOSITY - Numeric value modified by --verbose (+1) and --quiet (-1), e.g. --verbose --verbose --verbose --quiet gives value 2.

• GIT_TEST_NAME - Corresponds to the name of the current running test.

• GIT_TEST_PREVIOUS_CHECKED_OUT_COMMIT - When git-test runs tests on several commits, this variable contains the commit that was checked out for the previous test. Will be blank for the first commit checked out in a test run.

Example usage

Q: Wow, the following seems really complicated, do I really have to do all that just to run a test?

A: Not at all. The following is more meant to be an example exploring everything than can be done with environment variables more than a template to be copied for everyone.

Example of using environment variables in a build script named run-lint.sh:

#!/bin/sh

if [ "${GIT_TEST_VERBOSITY:-0}" -ge 1 ]
then
    if [ -f tslint.json ]
    then
        echo "Using tslint"
    else
        echo "Using eslint"
    fi
fi

PARENT=$(git log --pretty=%P -n 1 HEAD)
# If current commit is not a merge commit ...
if [ "$(echo "$PARENT" | wc -w)" -eq 1 ]
then
    if [ "$GIT_TEST_PREVIOUS_CHECKED_OUT_COMMIT" = "$PARENT" ]
    then
        # ... and package.json has not changed then skip running npm install.
        git diff --quiet "$PARENT" -- package.json || npm install
    else
        npm install
    fi
else
    npm install
fi

git tag -f current-git-test-"$GIT_TEST_NAME"
npm run lint

then when running

git test add --name=lint ./run-lint.sh
git test run --verbose --name=lint main..mybranch

the script will output which lint tool that will be used for each commit it tests.

---

The tag current-git-test-lint will here be moved along as git-test checks out new commits. This means for instance that you can follow the progress by just refreshing your gitk window instead of having to check the output in a specific terminal window.

If a test fails, the tag will be left on the last failing checked out commit, so you can easily fix it in the development worktree by running rebase --interactive --rebase-merges current-git-test-lint^ for then to edit the commit and fix the issue.

There is no "garbage collection" of such current test tags, so they will be left decaying if not actively cleaned up. So if this is a worthwile thing to do is completely up to you. But this is one example of what the GIT_TEST_NAME environment variable can be used for.

---

Running npm install can be quite expensive, but should really be run for every single test in order to ensure a proper environment. However by checking if the current test's parent just has been tested and if there is no changes in the package.json file, then we can skip running npm install because the parent would already have had the proper setup.

The same principle can be used for git submodules where you run git submodule update --init --recursive on the first test and then repeat only if .gitmodules changes later.