升级至Angular 19后测试失败：@flyInOut动画报错排查求助

将项目升级至Angular 19后，测试套件运行失败。项目为大型模块化架构，独立组件本不应影响测试流程，但执行ng test --watch命令时，测试运行至第1096个（共2158个）用例时触发如下错误，导致整个测试套件中断：

Chrome Headless 131.0.0.0 (Windows 10) ERROR
  An error was thrown in afterAll
  Error: NG05105: Unexpected synthetic property @flyInOut found. Please make sure that:
    - Make sure `provideAnimationsAsync()`, `provideAnimations()` or `provideNoopAnimations()` call was added to a list of providers used to bootstrap an application.
    - There is a corresponding animation configuration named `@flyInOut` defined in the `animations` field of the `@Component` decorator (see https://angular.dev/api/core/Component#animations).
  error properties: Object({ code: 5105 })
      at checkNoSyntheticProp (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/platform-browser/fesm2022/platform-browser.mjs:760:15)
      at NoneEncapsulationDomRenderer.setProperty (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/platform-browser/fesm2022/platform-browser.mjs:713:13)
      at elementPropertyInternal (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:13677:18)
      at Module.ɵɵsyntheticHostProperty (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:28127:9)
      at hostBindingFn (http://localhost:9876/_karma_webpack_/webpack:/node_modules/ngx-toastr/fesm2022/ngx-toastr.mjs:16:96)
      at processHostBindingOpCodes (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:13085:17)
      at refreshView (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:14932:9)
      at detectChangesInView (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:15098:9)
      at detectChangesInViewWhileDirty (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:14793:9)
      at detectChangesInternal (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:14775:9)
      at detectChangesInViewIfRequired (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:23652:5)
      at ApplicationRef.synchronizeOnce (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:23483:17)
      at ApplicationRef.synchronize (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:23450:18)
      at ApplicationRef._tick (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:23420:18)
      at apply (http://localhost:9876/_karma_webpack_/webpack:/node_modules/@angular/core/fesm2022/core.mjs:35125:29)
      at _ZoneDelegate.invoke (http://localhost:9876/_karma_webpack_/webpack:/node_modules/zone.js/fesm2015/zone.js:369:28)

注：仅在一个特定组件中使用@flyInOut动画，且已正确导入相关模块；此前测试运行正常，其他类似警告仅输出日志未引发测试中断。

已执行的排查操作 #

• 在karma.config中关闭测试随机排序
• 在测试配置中确保导入BrowserAnimationsModule等必要动画模块

求助问题 #

1. 如何定位引发该错误的组件或模块？
2. 为何该错误会终止测试而其他类似警告不会？

内容的提问来源于stack exchange，提问作者himtim