Documenting running tests in precommit hook

[vivekkalyan]

I want a git pre-commit hook that runs test on staged files before commits (similar to this)

This will require access to jest configs such as bail and findRelatedTests.

currently i am running this pre-commit

#!/bin/sh
PASS=true
echo "running tests"
CI=true npm test
if [[ "$?" == 0 ]]; then
    echo "\t\033[32mJest Tests Passed\033[0m"
else
    echo "\t\033[41mJest Tests Failed\033[0m"
    PASS=false
fi

but this results in every single test being run, which takes a long time. i want to effectively run

#!/bin/sh
STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep "js$")
if [[ "$STAGED_FILES" = "" ]]; then
    exit 0
fi

PASS=true
echo "running tests"
jest --bail --findRelatedTests $STAGED_FILES
if [[ "$?" == 0 ]]; then
    echo "\t\033[32mJest Tests Passed\033[0m"
else
    echo "\t\033[41mJest Tests Failed\033[0m"
    PASS=false
fi

I believe allowing for this will encourage better practices and am willing to take a stab at it if the maintainers think that it would be useful.

(also open to other solutions that people might use to achieve the same functionality)

[luftywiranda13]

any plan to use https://github.com/okonet/lint-staged?

you can then implement what I suggested in
#2336 (comment)

"scripts": {
  "precommit": "lint-staged",
  "test:staged": "cross-env CI=true react-scripts test --env=jsdom --findRelatedTests"
}

then

"lint-staged": {
  "src/**/*.js": [
    "test:staged",
    "git add"
  ]
}

for the env variable, use cross-env.. it is cross platform

hope it helps!

[vivekkalyan]

@luftywiranda13 thanks for that it works like a charm. i read that issue but must have glazed over ur solution, my bad!

should this be documented? seems like something that people would want to use as their apps getting bigger.

[gaearon]

Yes, would be great to document this.

[luftywiranda13]

@bowsplinter @gaearon ok, i'll make a PR 😊

[dan-weaver]

I may be doing something wrong, but I'm finding that my precommit hook fails (rejects the commit) when there are no tests found via the jest --findRelatedTests <file-name>. Anyone managed to fix this in their setups? Should jest not throw an error when there are no tests? That would seem more reasonable. If so, I can file an issue over there

[luftywiranda13]

@dan-weaver jest v22.1.0 exits without an error when no tests are found changelog

or you can pass --passWithNoTests

[dan-weaver]

Just saw that thanks.. Sorry for the additional noise here :)

[stale]

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