The problem was just in the setup of my test (not shown as part of the question). This callHome
function gets called anytime there is an Error via a decorated $exceptionHandler
. There was an error during the test on callHome
, so it got called again, and then just looped from there. I fixed that error, and now it all works just fine.
$httpBackend.flush() getting into inifinite loop
-
19-07-2023 - |
Frage
I want to be thorough, so please bear with me, there's going to be a lot here. We have a remote logging service function that will send us some client-side information when we want to. Something like this:
callHome: function(message){
var deferred, promise;
try{
if (someService.getRemoteLoggingEnabled())
{
//collect all the info into remoteLog
promise = $http.post("Logging", remoteLog);
wipeLog();
}
else
{
deferred = $q.defer();
promise = deferred.promise;
deferred.resolve();
}
}
catch(error)
{
try{
if (!promise)
{
deferred = $q.defer();
promise = deferred.promise;
}
deferred.reject(error.message);
}
catch(e2){}
}
return promise;
}
This all works just fine when running it in the actual app. The problem comes when trying to write unit tests for it. I have tests for when remote logging isn't enabled and for when there is an error. Those look like this:
it ("should resolve the promise with nothing when remote logging is turned off", inject(function($rootScope) {
remoteLoggingEnabled = false; //this is declared above a beforeEach that mocks getRemoteLoggingEnabled
var successSpy = jasmine.createSpy("success");
var failSpy = jasmine.createSpy("fail");
var promise = loggingService.callHome("Hello World");
promise.then(successSpy, failSpy);
$rootScope.$digest();
expect(successSpy).toHaveBeenCalledWith(undefined);
expect(failSpy).not.toHaveBeenCalled();
}));
it ("should reject the promise when there is an error with the error message", inject(function($rootScope) {
remoteLoggingEnabled = true;
var successSpy = jasmine.createSpy("success");
var failSpy = jasmine.createSpy("fail");
//angular.toJson is called while it's gathering client-side info
spyOn(angular, "toJson").andCallFake(function() {throw new Error("This is an error");});
var promise = loggingService.callHome("Hello World");
promise.then(successSpy, failSpy);
$rootScope.$digest();
expect(successSpy).not.toHaveBeenCalled();
expect(failSpy).toHaveBeenCalledWith("This is an error");
}));
These work great. I next wanted to add tests for when it actually made the makes the request. I put together a test like this:
it ("should resolve the promise with the http info when it makes a successful request", inject(function($rootScope, $httpBackend) {
remoteLoggingEnabled = true;
var successSpy = jasmine.createSpy("success");
var failSpy = jasmine.createSpy("fail");
$httpBackend.expect("POST", new RegExp("Logging"), function(jsonStr){
//not concerned about the actual payload
return true;
}).respond(200);
var promise = loggingService.callHome("Hello World");
promise.then(successSpy, failSpy);
$httpBackend.flush();
$rootScope.$digest();
expect(successSpy).toHaveBeenCalledWith(/*http info*/);
expect(failSpy).not.toHaveBeenCalled();
}));
However, this test just hangs. I stepped through the code and it gets stuck in the $rootScope.$digest()
call of $httpBackend.flush()
, specifically in this while loop:
while(asyncQueue.length) {
try {
asyncTask = asyncQueue.shift();
asyncTask.scope.$eval(asyncTask.expression);
} catch (e) {
clearPhase();
$exceptionHandler(e);
}
lastDirtyWatch = null;
}
I've inspected the asyncTask.expression
as it loops through, but I can't find any pattern to what it's doing.
I'm still getting a grasp on promises and how to use them, so I hope there's just something fundamentally wrong I'm doing here. Any help would be much appreciated.
Lösung