javascript - 未处理的 promise 拒绝警告 : TypeError: Converting circular structure to JSON with Jest + Angular

Question

使用 jest-preset-angular 执行单元测试，但收到警告为 UnhandledPromiseRejectionWarning: TypeError: Converting circular structure to JSON不确定是什么导致了错误，因此应用程序被卡住并且没有运行其他单元测试。

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

我不确定如何运行 Node --trace-warnings。看起来这是一个序列化问题，即使它只是一个警告，但不确定问题出在哪里。有没有更好的方法来查找异常

Answer 1

用 --detectOpenHandles 开 Jest .这将向您展示您的测试规范实际上有什么问题。对我来说，缺少 Angular Material 导入和服务模拟。系统可能会提示您添加 BrowserAnimationsModule ，正如南比在他的回答中提到的那样
包.json:

"test": "jest --detectOpenHandles"