Add partial automated support for Heroku CI builds

[dblandin]

Heroku CI currently exposes the following environment variables during CI builds:

• HEROKU_TEST_RUN_BRANCH: A string representing the branch of the commit under test
• HEROKU_TEST_RUN_COMMIT_VERSION: A string representing the commit version under test (This is the SHA in most cases)
• HEROKU_TEST_RUN_ID: A string uuid representing the unique ID of the test run

source: https://devcenter.heroku.com/articles/heroku-ci#configuration-using-app-json

The Code Climate test reporter relies on a git committed at timestamp to reliably render accurate test coverage annotations on codeclimate.com and on github.com via the browser extension.

For now, we can automatically apply the environment variables supported by Heroku CI, but a couple others will have to be manually supplied by the user:

export CI_NAME="heroku"
export GIT_COMMITTED_AT="$(date +%s)"

Related to: https://github.com/codeclimate/test-reporter/issues/226

[olivercodes]

is there a doc somewhere describing the setup process? Having some trouble with it

[maxjacobson]

Hi @olivercodes,

Good call out, we should add some Heroku CI -specific instructions to our examples directory and/or our docs.

For now: you should be able to reference our ordinary setup instructions, and just know that there's one difference required to use the test-reporter on Heroku CI: you'll need to export 2 environment variables before invoking the test reporter:

export CI_NAME="heroku"
export GIT_COMMITTED_AT="$(date +%s)"

I'm not sure what kind of trouble you were having, but I hope that unblocks you. Feel free to ping us again if not. If possible, please open a new issue to track it: https://github.com/codeclimate/test-reporter/issues/new

[olivercodes]

Sure! Thanks @maxjacobson, I'll ping you guys on email and open an issue