Using the jest-preset-angular to perform the unit test, but got an warning as UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON not sure what causing the error, due to this the application is stuck and not running the other unit test.
PASS src/app/pages/result/result-filter/result-filter.component.spec.ts (6.251 s)
PASS src/app/pages/result/search-navigation/search-navigation.component.spec.ts
PASS src/app/pages/result/filter-modal/filter-modal.component.spec.ts (5.699 s)
PASS src/app/app.component.spec.ts
PASS src/app/pages/test-type/test-type.component.spec.ts (12.857 s)
(node:3280) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
--> starting at object with constructor 'Object'
| property 'element' -> object with constructor 'Object'
| property 'componentProvider' -> object with constructor 'Object'
--- property 'parent' closes the circle
at stringify (<anonymous>)
at writeChannelMessage (internal/child_process/serialization.js:117:20)
at process.target._send (internal/child_process.js:808:17)
at process.target.send (internal/child_process.js:706:19)
at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3280) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3280) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:3281) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
--> starting at object with constructor 'Object'
| property 'element' -> object with constructor 'Object'
| property 'componentProvider' -> object with constructor 'Object'
--- property 'parent' closes the circle
at stringify (<anonymous>)
at writeChannelMessage (internal/child_process/serialization.js:117:20)
at process.target._send (internal/child_process.js:808:17)
at process.target.send (internal/child_process.js:706:19)
at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3281) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3281) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
(node:3279) UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON
--> starting at object with constructor 'Object'
| property 'element' -> object with constructor 'Object'
| property 'componentProvider' -> object with constructor 'Object'
--- property 'parent' closes the circle
at stringify (<anonymous>)
at writeChannelMessage (internal/child_process/serialization.js:117:20)
at process.target._send (internal/child_process.js:808:17)
at process.target.send (internal/child_process.js:706:19)
at reportSuccess (/Users/macbook/Projects/Playtime Projects/IDP/Idp.Bx.Ui/idp/node_modules/jest-worker/build/workers/processChild.js:67:11)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:3279) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:3279) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
RUNS src/app/pages/location/location.component.spec.ts
RUNS src/app/pages/signup/signup.component.spec.ts
RUNS src/app/pages/login/login.component.spec.ts
Test Suites: 10 passed, 10 of 20 total
Tests: 16 passed, 16 total
Snapshots: 1 obsolete, 5 passed, 5 total
Time: 2180 s
I am not sure how to run the node --trace-warnings. Looks like it a serialization issue, even it is just a warning but not sure where is the issue. Is there any better way to find the exception
Run jest with --detectOpenHandles. This will show you what is actually wrong with your test spec. For me, there were missing Angular Material imports and service mocks. You may be prompted to add the BrowserAnimationsModule, as Nambi alluded to in his answer
package.json:
"test": "jest --detectOpenHandles"
This message usually appears, if there is an error, that does not resolve into a standard exception.
As mentioned by @JamesBarret using jests detect open handle feature will provide you with a nice error message, telling you what the real problem behind this message is.
The handle --detectOpenHandles mentioned in the other message is deprecated though and was replaced with --detect-open-handles.
You can just use: (on your cli)
jest --detect-open-handles
Or in a package.json file:
"test": "jest --detect-open-handles"
Or as it was in my case an angular test:
ng test --detect-open-handles
Adding my answer to help someone if missed. In my case i have missed to import
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
Able to find the issue only when running one of the test case in isolation.