Don't force "--watch" into Jest

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Description

I want the tests to terminate after running once. But there doesn’t seem to be any way to disable this behavior except setting the CI environment variable like: "test": "CD=true react-scripts test --env=jsdom", in package.json. I traced the source of this behavior to these lines in test.js

// Watch unless on CI
if (!process.env.CI) {
  argv.push('--watch');
}

I understand that watching can be good when in the development cycle but when I want to run the tests in a pipeline or some script or git push hooks, I want to escape this mechanism.

Expected behavior

One of these

1. Make the npm test run only once and then make another one called npm run test:watch that watches.
2. Maybe add another package.json script called npm run test:once

Actual behavior

Tell us what actually happens.

Environment

react-scripts@0.4.1 node@6.5.0 npm@3.10.3

I can make a PR if this behavior is confirmed.

[gaearon]

From your PR:

• CI is already being handled
• COVERAGE doesn’t really seem like a good fit for me because you can already run npm test -- --coverage as explained in User Guide, and it works in watch mode just as fine.
• I explained why I don’t want to introduce NO_TEST_WATCH or similar in the comment above in this thread. As I also noted, I’m happy to revisit this at some point, but not now.

I understand your arguments well. I have considered each of these options (including leaving --watch in package.json) when I was integrating the test watcher. I made a choice to default to --watch unless CI is present, and I intend to stick to that choice for a while now. I appreciate your feedback and I’m happy to discuss this again in several months, but I don’t intend to change it now.

[heracek]

Simple hack is to prevent --watch is this:

react-scripts test --watchAll=false

This works because the code detects presence of --watchAll:

if (
  !process.env.CI &&
  argv.indexOf('--coverage') === -1 &&
  argv.indexOf('--watchAll') === -1
) {
  argv.push('--watch');
}