Problems mocking MockConnection error response

[mildfuzz]

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Current behavior
Test Repo - https://github.com/mildfuzz/angular-mockError

I am unable to test predicted HTTP error responses. Mockbackend can either send a response with an error code (which my app treats as a successful response in the test environment, but as an error in real world)

I am unable to send status codes with an error response in my tests, so I can not test any error handling my application might implements.

Expected behavior
at least one of the defined test cases passes

Minimal reproduction of the problem with instructions
Test Repo - https://github.com/mildfuzz/angular-mockError

this is a re-opening of issue #7471, which was closed due to lack of repro steps.

What is the motivation / use case for changing the behavior?
To be able to test all responses

Please tell us about your environment:
OsX

• Angular version: 2.0.X
  Angular 2.1.0

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]
  Chrome 54

• Language: TypeScript 2.0.3

• Node (for AoT issues): node --version = 6.9.1

[fetis]

I came across to the same problem. I would recommend to remove all redundant code from repository because it's not clear where to look in.

So briefly the problem looks next

http.get('some url')
  .map(value => {
    console.log('map');
   return value})
  .catch(() => console.log('catch')

and we have next mock response

backend.connections.subscribe((connection: MockConnection) => {
  connection.mockRespond(new Response(new ResponseOptions({
    status: 400
})))

so I expect it'll log catch as it happens with real backend. But actually it prints map all times.

The single way to fix it is to use connection.mockError()

[Ks89]

Exactly the same problem also with the latest stable release of angular. Same situation of @fetis .

To fix this problem I used:

backend.connections.subscribe((c: MockConnection) => c.mockError(new Response(new ResponseOptions({ status: 404}))));

The solution described into the official testing example HERE is not working.

[Koslun]

Duplicate issue: #13690.

#7135 points out that the current working way requires a double cast in TypeScript (connection.mockError(response as any as Error);). As MockError only accepts Error while the expected behavior is to get a proper Response object. There is a fix for that in PR #13104 made by @DzmitryShylovich.

Other than the official testing documentation @Ks89 linked, there is at least one other error in the API documentation at https://angular.io/docs/ts/latest/api/http/testing/index/MockBackend-class.html . Where it also seems to be assumed that responses with code 404 should result in a thrown error rather than a regular response.

Fixing this to generate the expected error might break some folks' tests, but think most or all of those tests were wrong to begin with.

[royling]

the current working way requires a double cast in TypeScript (connection.mockError(response as any as Error);). As MockError only accepts Error while the expected behavior is to get a proper Response object.

I tried to work around this problem by creating a class extending Response and implementing Error (type declared in types\node):

class ErrorResponse extends Response implements Error {
  name: any;
  message: any;
}

export function mockError(errorResponseOpts: any) {
  return new ErrorResponse(new ResponseOptions(errorResponseOpts));
}

and then mock error as:

mockConnection.mockError(mockError({status: 404}));

[JSchneidler]

Can we get an update on this? #13104 (the fix) was closed without an explanation.

I don't think these workarounds are a good long-term solution, though acceptable in the meantime if this is just a priority thing.

[alxhub]

Closing as this pertains to @angular/http which is now obsolete.

[nanoscz]

Cannot find module '@angular/http/testing' or its corresponding type declarations. [Angular 9]

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