feature request: set configuration from environment variables

[gibson042]

I have a need to invoke the same tests differently in the same CI setup; sometimes using the default reporter and sometimes using TAP. This precludes the possibility of using configuration files, and the particular setup involves automatic invocation in subdirectories in a way that makes varying arguments impractical.

But environment variables are passed down fully, so it would be very convenient if the executable understood e.g. AVA_TAP as indicating that the tap setting should be on unless overridden by an argument. And fortunately, this is extremely convenient with the yargs library already used by cli.js—basically as simple as .env('AVA') to support all arguments.

[novemberborn]

I'm reluctant to add configuration magic through environment variables. Configuration files (the JS ones) do have access to process.env though, could you use that to enable TAP conditionally?

[gibson042]

Nice idea. It works, but is a bit awkward because the subdirectories have package.json files with ava configuration so I need to explicitly specify --config and target a file that parses $projectDir/package.json to add overrides. But I understand (and in fact share) your apprehension around environment variables, and will understand if this case is not sufficiently compelling.

[novemberborn]

As long as those package.json files don't contain an "ava" key, AVA will walk up the directory tree looking for a JS file. Which receives the subdirectory if you export a factory function. Does that help?

[gibson042]

No, the package.json files do contain an "ava" key with relevant package-level configuration.

[novemberborn]

You could replace that with ava.config.js files that import from a parent file or somesuch. Convoluted, but manageable.

[gibson042]

Well, I already have a workaround as mentioned above, which is basically the inverse of that to avoid the convolution and protect against accidental omissions in the ava config files—"explicitly specify --config and target a file that parses $projectDir/package.json to add overrides". But it would sure be much nicer to instead invoke the test run with AVA_TAP=1 ava.