Console.log statements output nothing at all in Jest
Jestjsconsole.logJestjs Problem Overview
console.log
statements output nothing at all in Jest. This was working for me yesterday, and all of sudden, it's not working today. I have made zero changes to my config and haven't installed any updates.
I'm not using the --forceExit
option. Still seeing this issue.
Jestjs Solutions
Solution 1 - Jestjs
You can run both options together like this --watch --verbose false
if you want to also be watching the files and see the output.
for one time runs just do --verbose false
Solution 2 - Jestjs
Jest suppresses the console log message by default. In order to show the console log message, set silent option to false at the command line
set --silent=false
in the command line:
npm run test -- --silent=false
Solution 3 - Jestjs
As per comment on https://github.com/facebook/jest/issues/2441,
Try setting verbose: false (or removing it) in the jest options in package.json.
Solution 4 - Jestjs
Check for your command line flags in package.json
to see that you don't have --silent
in there.
Solution 5 - Jestjs
in addition to --verbose
option which can cause this as mentioned, be aware that the --watch
may also cause this bug.
Solution 6 - Jestjs
Also be sure that your jest config does not have silent: true
. In my case, I didn't realize that someone else had added that to our config.
I don't see it in the list of config options, but the command line flag is documented here.
Solution 7 - Jestjs
One of the potential reason that logging is not printing is due to console.log
has been mocked. Something as below
// jest-setup.js
global.console = {
// eslint-disable-next-line no-undef
log: jest.fn(), // console.log are ignored in tests
// log: console.log,
// Keep native behaviour for other methods, use those to print out things in your own tests, not `console.log`
error: console.error,
warn: console.warn,
info: console.info,
debug: console.debug,
};
// package.json
"jest": {
"preset": "react-native",
"moduleFileExtensions": [
"ts",
"tsx",
"js",
"jsx",
"json",
"node"
],
"setupFilesAfterEnv": [
"@testing-library/jest-native/extend-expect",
"<rootDir>/src/config/jest-setup.js"
],
"testMatch": [
"<rootDir>/src/**/__tests__/**/*.test.{ts,tsx}"
]
},
This is commonly used if you wish to disable console.log
in jest
Solution 8 - Jestjs
Try using console.debug()
instead.
Run console.debug('Message here', yourValueHere)
inside test function and it should show in the console output when running test script. You can verify if it works using Ctrl+F
and find Message here in the standard output.
This does the trick of showing output in the console, while it is not an answer quite on how to use console.log
I understand.
I am running @testing-library/jest-dom
and jest-junit 12.0.0
as devDependencies.
jest-junit
has a minimal configuration of
"jest-junit": {
"usePathForSuiteName": "true"
},
in package.json
. This is mainly to configure coverage reporting.
jest is configured like this:
"jest": {
"testMatch": [
"**/__tests__/**/*.[jt]s?(x)",
"**/?(*.)+(spec|test).[jt]s?(x)",
"!**/utilities.ts",
],
Solution 9 - Jestjs
This is a pretty old question and still there's no accepted answer. However, none of the suggested solutions worked for me (settings like --silent --verbose etc.). The main problem is that Jest changes the global console
object. So, the easiest solution is to not use the global console
object.
Instead import dedicated log functions from the console module and work with those:
import { error } from "console";
error("This is an error");
As easy as that.
Solution 10 - Jestjs
In my case, the issue was caused by [only] flag in:
it.only()
or test.only('some text',()=>{})
Solution 11 - Jestjs
According to the v27 docs silent
is what you want here. verbose false
(the default) prevents Jest from outputting the result of every test in a hierarchy while silent true
(the default) will:
>Prevent tests from printing messages through the console.
Use npx jest --silent false
if you want to run Jest with that option from the CLI. Tested this just now with console.log
and it works as expected.
Solution 12 - Jestjs
Having tried a few of the config options in the previous replies, using console.debug() instead of console.log() worked.
Solution 13 - Jestjs
Tried the advice given regarding jest config settings to no avail. Instead, in my case, the issue seemed related to not awaiting asynchronous code:
test("test", async () => {
console.log("Does output")
new Promise(resolve => {
// some expectation depending on async code
setTimeout(() => resolve(console.log("Does not output")) , 1)
})
})
Rather, awaiting the promise does output the async log:
test("test", async () => {
console.log("Does output")
await new Promise(resolve => {
// some expectation depending on async code
setTimeout(() => resolve(console.log("Does output")) , 1)
})
})
Possibly related background: https://github.com/facebook/jest/issues/2441
Solution 14 - Jestjs
Try using console.info() which is an alias for console.log(). I tried almost all the above answers but still console.log() didn't worked for me by any means. So, used console.info() which did the work.
Solution 15 - Jestjs
Solution 16 - Jestjs
In my case the problem was that the logs where made when the module is required, so before the start of an actual test case. Change from a top-level import
to using require
inside the test case fixed the problem.
Solution 17 - Jestjs
renaming my file to index.test.js
from index.spec.js
did the trick for me.