Jasmine Unit Test Promise function that is called multiple times based on the response from another promise function

Question

I want to unit test a function that is called multiple times based on a response from another function.

Similar to my question: Call a promise function multiple times until condition met from another promise function.

Here is the function

var monitorProgress = function() {  
    return getActiveTasks().then(function(res) { 
        if(res.length > 0) {
            progress = res[0].progress;
            if(progress !== 100){
                return $timeout(function(){
                    return monitorProgress();  // multiple calls
                },1000);
            }
            else {
                // exit
                console.log("done"); 
            }
        }
        else{
            console.log("done"); 
        }

    });  
};

Answer 1

Here is how I tested this function:

describe('monitorProgress function', function() {
    var response = null;
    var promise = null;
    var progress = 0;
    beforeEach(function() {   

        // fake the implementation of monitorProgress
        spyOn(SyncService,'monitorProgress').and.callFake(function() {

            progress++;

            // this mimics getActiveTasks promise and 
            // returns a promise with a res array length > 0
            var deferred = $q.defer();
            var res = [{ progress : progress }]; 
            deferred.resolve(res);

            // here the promise is returns 
            return deferred.promise.then(function(res) {
                console.log("getActiveTasks res: " + JSON.stringify(res,null,2))
                if(res.length > 0) {
                    progress = res[0].progress;
                    if(progress !== 100){
                        // keeps calling this until progress === 100
                        return SyncService.monitorProgress();
                    }
                    else {
                        // exit
                        console.log("exiting"); 
                    }
                }
                else {
                    // we never go here
                }
            });  
        });

        // now that the spy is set, call the function
        promise = SyncService.monitorProgress(); 
    }) 

    it("tracks that monitorProgress was called", function() {
        expect(SyncService.monitorProgress).toHaveBeenCalled();
    });

    it("tracks that monitorProgress returned a promise", function() {
        expect(promise).toBeDefined();
    });

    it("should return when progress is 100", function() { 
        // very important step
        $rootScope.$apply();

        // the final expectation
        expect(progress).toBe(100);
    }); 
});