mocha : how to run multiple JS test files under separate process environment - environment-variables

Question

I am new to Mocha so this might probably be a trivial question but couldn't yet find an answer:
I have a simple NodeJS project with the below package.json
{
"name": "test",
"version": "1.0.0",
"description": "test",
"main": "index.js",
"scripts": {
"test": "mocha"
},
"author": "davide talesco",
"license": "ISC",
"devDependencies": {
"chai": "^4.0.2",
"mocha": "^3.4.2"
}
}
and the following 2 tests files under test folder:
test1.js
process.env.NODE_ENV = 'test';
var chai = require('chai');
var should = chai.should();
describe('Test setProp', function(){
it('env variable should be test', function(done){
process.env.NODE_ENV.should.be.equal('test');
return done();
});
});
test2.js
process.env.NODE_ENV = 'prod';
var chai = require('chai');
var should = chai.should();
describe('Test setProp', function(){
it('env variable should be prod', function(done){
process.env.NODE_ENV.should.be.equal('prod');
return done();
});
});
when I run npm test the first test complete succesfully whilst the second fails as per below
ie-macp-davidt:crap davide_talesco$ npm test
> pc-lib#1.0.0 test /Users/davide_talesco/development/crap
> mocha
Test setProp
1) env variable should be test
Test setProp
✓ env variable should be prod
1 passing (16ms)
1 failing
1) Test setProp env variable should be test:
AssertionError: expected 'prod' to equal 'test'
+ expected - actual
-prod
+test
at Context.<anonymous> (test/test1.js:11:36)
npm ERR! Test failed. See above for more details.
its pretty clear that the tests are running under the same process...
my question is : how can I make them run under completely separate processes so each one can set its own environment?
Thanks,
Davide

Answer 1

One of the most simple ways is to use Unix find command:
find ./test -name '*.js' -exec mocha \{} \;
I'd recommend to use local mocha binaries to avoid troubles in case it isn't installed globally:
find ./test -name '*.js' -exec ./node_modules/.bin/mocha \{} \;
If you want to add that to package.json, please note that backslashes should be escaped:
...
"scripts": {
"test": "find ./test -name '*.js' -exec ./node_modules/.bin/mocha \\{} \\;"
},
...

Answer 2

If you want to abort testing as soon as a test file fails, you can do it like this:
find ./test -type f -name "*.js" -exec sh -c 'for n; do ./node_modules/.bin/mocha "$n" || exit 1; done' sh {} +

Answer 3

Alternatively you can use mocha-parallel-tests.
To install:
https://www.npmjs.com/package/mocha-parallel-tests
To use:
"scripts": {
"test": "mocha-parallel-tests"
},
Nice thing is that it is a proper mocha runner so you can configure reports and pass standard mocha configuration like bail.