After updating to Angular 19, some unit tests fail with NullInjectorError: No provider for...

After updating my Angular project (including Angular Material) to v19, I am getting new errors like the following in my unit tests:

NullInjectorError: R3InjectorError(Standalone[MyComponent])[CdkStepper -> CdkStepper -> ChangeDetectorRef -> ChangeDetectorRef]:
NullInjectorError: No provider for ChangeDetectorRef! in vendor.js (line 81434)
error properties: Object({ ngTempTokenPath: null, ngTokenPath: [ 'CdkStepper', 'CdkStepper', 'ChangeDetectorRef', 'ChangeDetectorRef' ] })


or

NullInjectorError: R3InjectorError(Standalone[MyComponent])[CdkStepper -> CdkStepper -> ElementRef -> ElementRef]:
NullInjectorError: No provider for ElementRef! in vendor.js (line 81434)
error properties: Object({ ngTempTokenPath: null, ngTokenPath: [ 'CdkStepper', 'CdkStepper', 'ElementRef', 'ElementRef' ] })


What I noticed is that the failing tests are set up like the following:

TestBed.configureTestingModule({
imports: [MyComponent],
providers: [
{ provide: CdkStepper, useClass: CdkStepper },
],
});


In this example the provider for CdkStepper is necessary, otherwise I'm getting: NullInjectorError: No provider for CdkStepper!

In Angular 18, those unit tests passed. What is the reason that this tests now fail? How can I fix the tests?

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