$httpBackend.flush fails when service throws error

Question

I have created a service to serve as a client of my backend API. When backend returns an error, my service should handle that problem by rethrowing the error with more readable message to be later caught at controller level:

function readApi() {
        return $http.get("adress").catch(function (e) {
            if (e.status === 400) {
                throw new Error("API call not succeded...");
            }
        }).then(function (requestResult) {
            // further processing of result
        });
    }

Then, I tried to write a spec in Jasmine testing this behaviour:

    it('throw proper error for 400 reponse from API', function () {
    httpBackend.expectGET('address').respond(400, '');

    expect(function () {
        myService.readApi();
    }).toThrow();

    httpBackend.flush();
});

afterEach(function () {
    httpBackend.verifyNoOutstandingExpectation();
    httpBackend.verifyNoOutstandingRequest();
});

Unfortunately the error seems to be thrown from httpBackend.flush() instead my function, leading to failure of test.

Am using it wrong or is it error in httpBackend mock? How can i perform such test?

EDIT

I tried @tomepejo's answer and it almost worked:

it('throw proper error for 400 reponse from API', function () {
    httpBackend.expectGET('address').respond(400, '');

    expect(function () {
        myService.readApi();
        httpBackend.flush();
    }).toThrow();
});

afterEach(function () {
   //httpBackend.verifyNoOutstandingExpectation();
   httpBackend.verifyNoOutstandingRequest();
});

Unfortunately uncomenting afterEach's body leads to error:

 Error: [$rootScope:inprog] $digest already in progress
http://errors.angularjs.org/1.3.14/$rootScope/inprog?p0=%24digest
   at .../Scripts/Lib/angular.js:63:12
   at beginPhase (.../Scripts/Lib/angular.js:14755:15)
   at Scope.$digest (.../Scripts/Lib/angular.js:14197:9)
   at Function.$httpBackend.verifyNoOutstandingExpectation (.../Scripts/Lib/angular-mocks.js:1550:38)
   at Object.<anonymous> (.../ApiClientTest.js:94:29)

I think it doesn't need mentioning, that this afterEach is useful in numerous other tests and pasting those calls at the end on every test (or extracting exception testing to another describe) doesn't feel like a right way to do it.

Or maybe it is a bug in an angular-mocks library and I should file a bug report?

André Godoy André Godoy · Accepted Answer · 2016-05-03T17:44:16

You can achieve what you want by passing false to the verifyNoOutstandingExpectation() function, but in order to not interfere with the $digest cycle of other tests, you can do the following:

var shouldDigest;
beforeEach(inject(function (...) {
    //your initialization here

    shouldDigest = true;
}));

afterEach(function () {
   httpBackend.verifyNoOutstandingExpectation(shouldDigest);
   httpBackend.verifyNoOutstandingRequest();
});

and in this test specifically:

it('throw proper error for 400 reponse from API', function () {
    httpBackend.expectGET('address').respond(400, '');

    expect(function () {
        myService.readApi();
        httpBackend.flush();
    }).toThrow();
    shouldDigest = false;
});

Source and explanation here: http://nikas.praninskas.com/angular/2015/11/20/quickie-httpbackend-digest-in-progress/

$httpBackend.flush fails when service throws error

2 Answers