javascript - Found the synthetic property @enterAnimation. Please include either "BrowserAnimationsModule" or "NoopAnimationsModule" in your application. Angular4

Question

When running Karma to test my Angular4 application, I get this error Found the synthetic property @enterAnimation. Please include either "BrowserAnimationsModule" or "NoopAnimationsModule" in your application. though I already imported the module in app.module.ts

        // animation module
        import { BrowserAnimationsModule } from '@angular/platform-browser/animations'; 
    ...
@NgModule({
    imports: [...
        BrowserAnimationsModule,
        ...
      ],

and in my component:

 import { Component, OnInit } from '@angular/core';
    import {
      trigger,
      state,
      style,
      animate,
      transition
    } from '@angular/animations';

    @Component({
      selector: 'app-about',
      animations: [
        trigger(
          'enterAnimation', [
            transition(':enter', [
              style({ transform: 'translateX(100%)', opacity: 0 }),
              animate('500ms', style({ transform: 'translateX(0)', opacity: 1 }))
            ]),
            transition(':leave', [
              style({ transform: 'translateX(0)', opacity: 1 }),
              animate('500ms', style({ transform: 'translateX(100%)', opacity: 0 }))
            ])
          ]
        ),
        trigger(
          'enterAnimationVetically', [
            transition(':enter', [
              style({ transform: 'translateY(100%)', opacity: 0 }),
              animate('500ms', style({ transform: 'translateY(0)', opacity: 1 }))
            ]),
            transition(':leave', [
              style({ transform: 'translateY(0)', opacity: 1 }),
              animate('500ms', style({ transform: 'translateY(100%)', opacity: 0 }))
            ])]
        )
      ],
...

The application runs perfectly with ng serve yet, I got this error with karma.

Answer 1

Future readers: you can also get this exact error, when you forget to place

animations: [ <yourAnimationMethod()> ]

on your @Component ts file.

that is if you're using [@yourAnimationMethod] on the HTML template.