ReferenceError: You are trying to `import` a file after the Jest environment has been torn down
Full error message
I have a component that makes use of Animated component from react native. I started writing a test case to simulate onPress of a component, which calls a function that has Animated.timing in it, and setState.
running jest works fine, but the tests never stops running, and one unrelated test case that I've written before never seem to pass now (which passed before).
running jest --watch, I get this error:
ReferenceError: You are trying to `import` a file after the Jest environment has been torn down.
at Function.bezier (node_modules/react-native/Libraries/Animated/src/Easing.js:113:21)
at ease (node_modules/react-native/Libraries/Animated/src/Easing.js:34:24)
at TimingAnimation._easing (node_modules/react-native/Libraries/Animated/src/Easing.js:133:18)
at TimingAnimation.onUpdate (node_modules/react-native/Libraries/Animated/src/animations/TimingAnimation.js:107:45)
RUNS src/__tests__/SlideDownMenu.test.js
/home/nrion/Desktop/mobile-ui/PriceInsight_app/node_modules/react-native/Libraries/Animated/src/Easing.js:114
return _bezier(x1, y1, x2, y2);
^
TypeError: _bezier is not a function
at Function.bezier (/home/nrion/Desktop/mobile-ui/PriceInsight_app/node_modules/react-native/Libraries/Animated/src/Easing.js:224:12)
at ease (/home/nrion/Desktop/mobile-ui/PriceInsight_app/node_modules/react-native/Libraries/Animated/src/Easing.js:94:21)
at TimingAnimation._easing (/home/nrion/Desktop/mobile-ui/PriceInsight_app/node_modules/react-native/Libraries/Animated/src/Easing.js:255:16)
at TimingAnimation.onUpdate (/home/nrion/Desktop/mobile-ui/PriceInsight_app/node_modules/react-native/Libraries/Animated/src/animations/TimingAnimation.js:138:14)
at ontimeout (timers.js:386:11)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5)
Link to repl
https://repl.it/repls/PartialGrimyMetadata
Environment:
OS: Linux 4.14
Node: 6.14.2
Yarn: 1.7.0
npm: 3.10.10
Watchman: Not Found
Xcode: N/A
Android Studio: Not FoundSolutionsource: stackoverflow \u2197
OK, found a solution. Should use jest.useFakeTimers(). Note: Put the code above just after import section in your test file. === Edited === You can read more about how useFakeTimers work here: https://jestjs.io/docs/timer-mocks Simply, it mocks functions like setTimeout, setInterval, etc. If you do not use jest.useFakeTimers(), you may have async tests that take long to complete, and warnings like the following might be thrown. You are trying to access a property or method of the Jest environment after it has been torn down.
API access
Get this solution programmatically \u2014 free, no authentication.
curl https://depscope.dev/api/error/8658871d6672358565253df1ace853675e02b2e54b4ed623951fff8655a27e8fhash \u00b7 8658871d6672358565253df1ace853675e02b2e54b4ed623951fff8655a27e8f