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Don't force "--watch" into Jest #784
Description
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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
- Make the
npm testrun only once and then make another one callednpm run test:watchthat watches. - 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.
Activity
gaearon commentedon Sep 27, 2016
Is there a reason you don’t want to set
CI=truewhen running them in a script or git hooks? This is the intended usage. I understand it’s slightly inconvenient, but we need to teach people to use the watcher (and if it’s not good, nudge them to report problems so it gets better). So it seems to me that asking you to specifyCI=truein scripts and hooks is a fair tradeoff.alexewerlof commentedon Sep 27, 2016
Yes, it feels like a hack to set CI=true for a git hook that has nothing to do with CI.
IF we have to use environment variables for this, maybe we can go for a more intuitive name like "WATCH" or "TEST_WATCH" or "WATCH_TESTS".
I have watched your talk about how Redux and hot reloading can improve developer productivity by shortening the code-run-debug loop and I totally understand why it's a good idea to keep the test runner watch the files. But the test command has a bit of an odd behaviour if you've worked with anything like Mocha or even Jest. The test runners by default run the test once and if someone wants the watch behavior, s/he opts-in. I feel that CRA is targeted at newbies and tries to help them by using best practices, but the CI=true solution seems a bit hacky and hard to grok.
gaearon commentedon Sep 27, 2016
I understand your concerns and
CIis indeed not the most obvious way to do it. It is documented, however, and I think it’s a reasonable compromise between having things work automatically, a good default setup, and a possibility of extensions. For now, Create React App prioritizes interactivity and heuristics over explicit configuration. This means that some advanced scenarios get a little bit more awkward but since you’re using them in code, you might as well put a comment there. In the future we might reconsider this (and even add some configuration). But today is not that day yet.gaearon commentedon Sep 27, 2016
Going to close this for reasons above. Happy to revisit in a few months if you’d like.
Sorry for the inconvenience!
added support for disabling test watch with more variable names
alexewerlof commentedon Sep 28, 2016
Sorry for being so persistent.
I made a PR to demonstrate one possible solution.
Another (better IMHO) solution is not to do anything based on the environment variables and let the "test" script in
package.jsondecide that. Travis runsnpm testby default. So we can have something liketest:devortest:watchthat can be used in the development cycle.Another solution is to keep the
--watchin the "test" script. This way if someone doesn't like it, they can easily remove --watch from their package.json rather than having to set an env variable. Everybody wins: your code will be simpler, newbie users won't notice a change and pro devs will have an option to opt out.I'll be happy to help with another PR whatever makes more sense (and update the docs).
gaearon commentedon Sep 28, 2016
From your PR:
CIis already being handledCOVERAGEdoesn’t really seem like a good fit for me because you can already runnpm test -- --coverageas explained in User Guide, and it works in watch mode just as fine.NO_TEST_WATCHor 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
--watchinpackage.json) when I was integrating the test watcher. I made a choice to default to--watchunlessCIis 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 commentedon May 28, 2018
Simple hack is to prevent
--watchis this:react-scripts test --watchAll=falseThis works because the code detects presence of
--watchAll:tshinnic commentedon Jun 5, 2018
Having a problem making your wonderful workaround work nicely as CRA 1.1.4 is insisting on using a previous copy 20.0.4 of Jest, which doesn't (?) support
--watchAll. I nastily installed jest@23 underneath the existing node_modules\react-scripts and now your workaround makes me happy.rudasn commentedon Jun 27, 2018
Just a heads up, you can also use
--coverageto disable watch mode.slorber commentedon Aug 22, 2018
Hi @gaearon
To update snapshots without the --watch, I can do `"test:updateSnapshots": "CI=true npm run test -- --updateSnapshot",``
The
CI=truefeels a bit weird here as I run this command locally, totally unrelated to CI.I'll be fine with it, just reporting the issue
mrmckeb commentedon Nov 6, 2018
@gaearon A problem here is that
CI=truedisables color in tests, which is not ideal. I'd like to see another solution here, but for now I'm using @heracek's solution.Exits shell after testing, fixes #14
ScottMcCormack commentedon Dec 19, 2018
I'm a bit confused by the syntax
-- --coverageWhy doesn't this operate the same as
--coverage?mrmckeb commentedon Dec 19, 2018
@ScottMcCormack, that tells
npmto pass the flag through, otherwise it would be considered annpmflag. Note that this is not required inyarn.