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Flush on TestOperation does not work if Query Document contains a Fragment #2356
Description
Describe the bug
The ApolloTestingController removes all flushed fields, which are described in a fragment.
To Reproduce
Having the following query:
query GetBenefitOptions {
benefits {
...BenefitOption
}
}
fragment BenefitOption on Benefit {
__typename
id
description
price {
price
}
}and code in the component:
public readonly options$: Observable<BenefitOptionFragment[]> = this.getBenefitOptions.watch().valueChanges.pipe(
map((result) => result.data.benefits),
tap((val) => console.log(JSON.stringify(val)))
);I am doing the following test case:
// The change of the inputs should trigger the query
const op: TestOperation<GetBenefitOptionsQuery> = controller.expectOne(GetBenefitOptionsDocument);
// Mock the GraphQL response
op.flushData({
__typename: 'Query',
benefits: [
{
__typename: 'PrivateBenefit',
id: 'benefit-1' as BenefitID,
description: 'Basic Cleaning',
price: { price: 50 },
},
{
__typename: 'PrivateBenefit',
id: 'benefit-2' as BenefitID,
description: 'Premium Cleaning',
price: { price: 100 },
},
{
__typename: 'PrivateBenefit',
id: 'benefit-3' as BenefitID,
description: 'Deep Cleaning',
price: { price: 150 },
},
],
});The component logs:
[{}, {}, {}]Changing the query to not using a fragment
query GetBenefitOptions($filter: BenefitsFilterInput!) {
benefits {
__typename
id
description
price {
price
}
}
}
let the component produce the expected output
[{"__typename":"PrivateBenefit","id":"benefit-1","description":"Basic Cleaning","price":{"price":50}},{"__typename":"PrivateBenefit","id":"benefit-2","description":"Premium Cleaning","price":{"price":100}},{"__typename":"PrivateBenefit","id":"benefit-3","description":"Deep Cleaning","price":{"price":150}}]Expected behavior
TestingController will also work with fragments.
Environment:
├── @angular/cli@18.2.12
├── @angular/core@18.0.5 overridden
├── @apollo/client@3.13.4
├── apollo-angular@10.0.3
├── graphql@16.9.0
└── typescript@5.4.4
Additional context
Using Karma to execute the tests.
Benefit is an interface.
Activity
reicheltp commentedon Mar 20, 2025
I digged a little bit deeper into this topic and discovered that this problem only occurs when using interfaces with fragment.
For the InMemoryCache it is mandatory to provide all possible types. Is there any way to tell the Test Executor that a fragment for an interface is valid for the actual implementation?
Alternatively, we can maybe tell apollo to ignore the actual types and just return everything we flushed? Will this break other stuff?