Unit-testing Angular services and directives - unit-testing

Being new to Angular (and to tell the truth, JS itself) I'm strugling with isolated unit-testing of services and directives.
I tried to compile solution from different examples found in the internet, but failed.
I've got a service:
angular.module('myApp.services', [])
.factory('autoCmpltDataSvc', function ($http) {
return {
source: function (request, response) {
$http({
method: 'jsonp',
url: 'http://ws.geonames.org/searchJSON?callback=JSON_CALLBACK',
params: {
featureClass: "P",
style: "full",
maxRows: 12,
name_startsWith: request.term
}
}).success(function (data, status) {
response($.map(data.geonames, function (item) {
return {
label: item.name + (item.adminName1 ? ", " + item.adminName1 : "") + ", " + item.countryName,
value: item.name,
geonameId: item.geonameId
}
}));
});
}
}
});
I'd like to fake the interaction with actual web service passing predefined array and check that it returns correct response when passing different values for request.term.
The other task is to unit-test a directive (wrapper around jquery autocomplete)
angular.module('myApp.directives', [])
.directive('autocomplete', function (autoCmpltDataSvc) {
return {
restrict: 'E',
replace: true,
transclude: true,
template: '<input id="DstnSlctr" ng-model="autocomplete" type="text"/>',
link: function (scope, element, attrs) {
scope.$watch(autoCmpltDataSvc, function () {
element.autocomplete({
source: autoCmpltDataSvc.source,
select: function (event, ui) {
scope[attrs.selection] = ui.item.value;
scope[attrs.selectionid] = ui.item.geonameId;
scope.$apply();
}
});
});
}
}
});
I'd like to fake the call to the service with some predefined array and check that the scope is modified correctly.
Is it possible to test those in isolation or should I use only e2e tests for this task?
Thanks in advance for responses!
Ksenia

For the service, essentially what you will want to do is use $httpBackend in your unit test. What angular does is it has an $httpBackend that it uses (behind $http). But when you are injecting it into a unit test, it magically knows and intercepts the calls.
Per doc, what you need to do is stage your http requests by providing real urls (and what params you will pass in unit test), in beforeEach and also add an afterEach. NOTE: I believe doc has a typo
var $http; // and should probably be: var $httpBackend
For directives, it depends. If you've created the entire directive, then unit testing is probably a much easier road. When wrapping plugins, then you might consider a couple of things. Firstly, write e2e tests may be a good first step. Secondly, see if your own code (in the directive) could be put into a helper method and that part may be unit testable.

Related

Unit testing NestJS controller with request

My Controller function definition looks like that:
async login(#Req() request, #Body() loginDto: LoginDto): Promise<any> {
How I could prepare/mockup Request to provide first argument of function from Jest test?
Inside funciton I am setting headers using request.res.set. Should I somehow pass real Request object to function and then check if header is set or rather mockup whole Request object and check if set function was called?
I managed to do that mocking requests and response using node-mocks-http library.
const req = mocks.createRequest()
req.res = mocks.createResponse()
and then passing this as an argument.
const data = await authController.login(req, loginDto)
expect(req.res.get('AccessToken')).toBe(token.accessToken)
I followed a different approach and instead of using node-mocks-http library I used #golevelup/ts-jest, also, instead of testing if the function returns some value, like res.json() or res.status(), I checked if the function was called with the value I wanted to.
I borrowed this approach from Kent C. Dodds's testing workshop, take a look for similar ideas. Anyway, this is what I did in order to mock the Response dependency of my Controller's route:
// cars.controller.spec.ts
import { createMock } from '#golevelup/ts-jest';
const mockResponseObject = () => {
return createMock<Response>({
json: jest.fn().mockReturnThis(),
status: jest.fn().mockReturnThis(),
});
};
... ommited for brevity
it('should return an array of Cars', async () => {
const response = mockResponseObject();
jest
.spyOn(carsService, 'findAll')
.mockImplementation(jest.fn().mockResolvedValueOnce(mockedCarsList));
await carsController.getCars(response);
expect(response.json).toHaveBeenCalledTimes(1);
expect(response.json).toHaveBeenCalledWith({ cars: mockedCarsList });
expect(response.status).toHaveBeenCalledTimes(1);
expect(response.status).toHaveBeenCalledWith(200);
});
And that's it, I think that the implementation details aren't that important but in any case I'll leave the link to the Github repo where you can find the whole project.

How do I inject a mock dependency into an angular directive with Jasmine on Karma

I have the following directive:
function TopLevelMenuDirective ($userDetails, $configuration) {
return {
restrict:'A',
templateUrl: staticFilesUri + 'templates/TopLevelMenu.Template.html',
scope: {
activeTab: '='
},
link: function (scope, element, attributes) {
var userDetails = $userDetails;
if ($userDetails) {
scope.user = {
name: userDetails.name ? userDetails.name : 'KoBoForm User',
avatar: userDetails.gravatar ? userDetails.gravatar: (staticFilesUri + '/img/avatars/example-photo.jpg')
};
} else {
scope.user = {
name: 'KoBoForm User',
avatar: staticFilesUri + '/img/avatars/example-photo.jpg'
}
}
scope.sections = $configuration.sections();
scope.isActive = function (name) {
return name === scope.activeTab ? 'is-active' : '';
}
}
}
}
I want to mock the dependencies to unit test the different code paths with values known by the unit tests. I have the following sample unit test:
it('should set $scope.user to values passed by $userDetails',
inject(function($compile) {
var element = '<div top-level-menu></div>';
element = $compile(element)($scope);
$scope.$apply();
expect(element.isolateScope().user.name).toBe('test name');
expect(element.isolateScope().user.avatar).toBe('test avatar');
}
));
This gives me two problems.
First, since the template is in an external file, when it loads it tries to fetch it and errors out beacause the file is nowhere to be found, which is logical since it's in a test environment and not an actual server.
Second, there's no apparent way to mock the dependencies injected into the directive through its constructor. When testing controllers you can use the $controller service, but since directives are instantiated indirectly by compiling an html tag with a passed scope, there's no way to instantiate it directly (e.g. there's no analogous $directive). This impedes me from setting $userDetails.name and $userDetails.gravatar to 'test name' and 'test avatar' respectively.
How do I get the directive to compile properly and run with a custom $userDetails dependency?
To load the template file you must configure karma-ng-html2js-preprocessor in karma.
First, visit this page and follow the installation instructions. Then, you need to add a couple of entries in your karma.config.js file:
files: [
'templates/*.html'
],
this tells karma to load all html files in the templates folder (if your templates are somewhere else, put that folder there).
preprocessors: { '**/*.html': 'ng-html2js' },
this tells karma to pass all html files through the ng-html2js preprocessor, which then transforms them into angular modules that put the templates into the $templateCache service. This way, when $httpBackend queries the "server" for the template, it get's intercepted by the template cache and the correct html is returned. All fine here, except for the template's URL: it has to match the templateUrl property in the directive, and ng-html2js passes the full path as the uri by default. So we need to transform this value:
ngHtml2JsPreprocessor: {
cacheIdFromPath: function(filepath) {
var matches = /^\/(.+\/)*(.+)\.(.+)$/.exec(filepath);
return 'templates/' + matches[2] + '.' + matches[3];
}
},
this receives filepath and passes it through a regular expression that extracts the path, file name and extension into an array. You then prepend 'templates/ to the file name and extension and you get the expected uri.
After all this is done making the template available is a matter of loading the module before your test is run:
beforeEach(module('templates/TopLevelMenu.Template.html'));
keep in mind, module is an external service located in angular-mocks.js.
for injecting a custom service into the directive you need to override the service's provider:
beforeEach(module(function ($provide) {
$provide.provider('$userDetails', function () {
this.$get = function () {
return {
name: 'test name',
gravatar: 'test avatar'
};
}
});
}));
$provide is the service that provides your providers. So, if you want to inject a mock dependency you override the provider here.
With that code executing before your test you'll have a mock $userDetails service that returns your predefined strings.

How do you mock a service in AngularJS when unit testing with jasmine?

Let's say I have a service shop that depends on two stateful services schedule and warehouse. How do I inject different versions of schedule and warehose into shop for unit testing?
Here's my service:
angular.module('myModule').service('shop', function(schedule, warehouse) {
return {
canSellSweets : function(numRequiredSweets){
return schedule.isShopOpen()
&& (warehouse.numAvailableSweets() > numRequiredSweets);
}
}
});
Here are my mocks:
var mockSchedule = {
isShopOpen : function() {return true}
}
var mockWarehouse = {
numAvailableSweets: function(){return 10};
}
Here are my tests:
expect(shop.canSellSweets(5)).toBe(true);
expect(shop.canSellSweets(20)).toBe(false);
beforeEach(function () {
module(function ($provide) {
$provide.value('schedule', mockSchedule);
});
});
Module is a function provided by the angular-mocks module. If you pass in a string argument a module with the corresponding name is loaded and all providers, controllers, services, etc are available for the spec. Generally they are loaded using the inject function. If you pass in a callback function it will be invoked using Angular's $injector service. This service then looks at the arguments passed to the callback function and tries to infer what dependencies should be passed into the callback.
Improving upon Atilla's answer and in direct answer to KevSheedy's comment, in the context of module('myApplicationModule') you would do the following:
beforeEach(module('myApplicationModule', function ($provide) {
$provide.value('schedule', mockSchedule);
}));
With CoffeeScript I run in some issues so I use null at the end:
beforeEach ->
module ($provide) ->
$provide.value 'someService',
mockyStuff:
value : 'AWESOME'
null
You can look here for more info
https://docs.angularjs.org/guide/services#unit-testing
You want to utilize the $provide service. In your case
$provide.value('schedule', mockSchedule);
As you are using jasmine, there is an alternative way to mock the calls with jasmine's spies (https://jasmine.github.io/2.0/introduction.html#section-Spies).
Using these you can be targeted with your function calls, and allow call throughs to the original object if required. It avoids clogging up the top of your test file with $provide and mock implementations.
In the beforeEach of your test I would have something like:
var mySchedule, myWarehouse;
beforeEach(inject(function(schedule, warehouse) {
mySchedule = schedule;
myWarehouse = warehouse;
spyOn(mySchedule, 'isShopOpen').and.callFake(function() {
return true;
});
spyOn(myWarehouse, 'numAvailableSweets').and.callFake(function() {
return 10;
});
}));
and this should work in similar fashion to the $provide mechanism, noting you have to provide local instances of the injected variables to spy on.
I recently released ngImprovedTesting module that should make mock testing in AngularJS way easier.
In your example you would only have to replace in your Jasmine test the ...
beforeEach(module('myModule'));
... with ...
beforeEach(ModuleBuilder.forModule('myModule').serviceWithMocks('shop').build());
For more information about ngImprovedTesting check out its introductory blog post:
http://blog.jdriven.com/2014/07/ng-improved-testing-mock-testing-for-angularjs-made-easy/
It is simpler to put the mock on the module like this:
beforeEach(function () {
module('myApp');
module({
schedule: mockSchedule,
warehouse: mockWarehouse
}
});
});
you can use injection to get reference to these mocks for pre test manipulations :
var mockSchedule;
var mockWarehouse;
beforeEach(inject(function (_schedule_, _warehouse_) {
mockSchedule = _schedule_;
mockWarehouse = _warehouse_;
}));
I hope my answer is not that useless, but you can mock services by $provide.service
beforeEach(() => {
angular.mock.module(
'yourModule',
($provide) => {
$provide.service('yourService', function() {
return something;
});
}
);
});

AngularJS - Unit testing file uploads

As you know, inside unit tests it's built-in angularjs feature to mock XHR requests with $httpBackend - this is nice and helpful while writing unit tests.
Recently, I met with need of mocking XHR in case of file upload and discovered some problems.
Consider following code:
var xhr = new XMLHttpRequest();
xhr.upload.addEventListener("progress", uploadProgress(event), false);
xhr.addEventListener("load", uploadComplete(event), false);
xhr.addEventListener("error", uploadError(event), false);
xhr.addEventListener("abort", uploadAbort(event), false);
xhr.open("POST", 'some url');
xhr.send(someData);
What I want to do is to do unit testing of such a code with mocking of XHR requests, but it's not possible do it because there is no $http service used here.
I tried this (and it's working and could be mocked with $httpBackend):
$http({
method: 'POST',
url: 'some url',
data: someData,
headers: {'Content-Type': undefined},
transformRequest: angular.identity})
.then(successCallback, errorCallback);
But in this case I don't know how to implement 'progress' callback and 'abort' callback (they are essential and required in case I am working on now).
I've seen information that latest Angular supports progress callback for promises (not sure though whether it's integrated with $http service), but what about abort callback?
Any ideas or maybe your met with something similar before?
If the $http service doesn't give you everything you need, you can still unit test the first block of code. First of all, change your code to use Angular's $window service. This is just a wrapper service, but it allows you to mock the object in your tests. So, you'll want to do this:
var xhr = new $window.XMLHttpRequest();
Then in your tests, just mock it and use spies.
$window.XMLHttpRequest= angular.noop;
addEventListenerSpy = jasmine.createSpy("addEventListener");
openSpy = jasmine.createSpy("open");
sendSpy = jasmine.createSpy("send");
xhrObj = {
upload:
{
addEventListener: addEventListenerSpy
},
addEventListener: addEventListenerSpy,
open: openSpy,
send: sendSpy
};
spyOn($window, "XMLHttpRequest").andReturn(xhrObj);
From there, you can make the different spies return whatever you want for the different tests.
You should mock $http and control any deferred, as you want more control over your test. Basically, mock $http provider and serve a custom implementation that exposes its deferred, then play with it.
You should not worry whether $http is working right or not, because it is supposed to, and is already tested. So you have to mock it and only worry testing your part of the code.
You should go something like this:
describe('Testing a Hello World controller', function() {
beforeEach(module(function($provide) {
$provide.provider('$http', function() {
this.$get = function($q) {
return function() {
var deferred = $q.defer(),
promise = deferred.promise;
promise.$$deferred = deferred;
return promise;
}
};
});
}));
it('should answer to fail callback', inject(function(yourService, $rootScope) {
var spyOk = jasmine.createSpy('okListener'),
spyAbort = jasmine.createSpy('abortListener'),
spyProgress = jasmine.createSpy('progressListener');
var promise = yourService.upload('a-file');
promise.then(spyOk, spyAbort, spyProgress);
promise.$$deferred.reject('something went wrong');
$rootScope.$apply();
expect(spyAbort).toHaveBeenCalledWith('something went wrong');
}));
});
And your service is simply:
app.service('yourService', function($http) {
return {
upload: function(file) {
// do something and
return $http({...});
}
};
});
Just note that promises notification is only available in the latest RC release. So, if you can't use it, just elaborate a little more the example and mock the XHR events and so.
Also note that you should preferably have one test case for each of the callbacks (fail, success and progress), in order to follow KISS principle.

How do unit test with angular-translate

I have uses angular translate from here (http://pascalprecht.github.io/angular-translate/) and it's just work fine, but it break my controller's unit test whith Error:
Unexpected request: GET scripts/i18n/locale-en.json
I don't understant why?
I use yeoman and test with karma.
app.js:
'use strict';
(function() {
angular.module('wbApp', ['authService', 'authUserService', 'checkUserDirective', 'ui.bootstrap', 'pascalprecht.translate'])
.config(function($routeProvider) {
$routeProvider
.when('/', {
templateUrl: 'views/login.html',
controller: 'LoginCtrl',
access: {
isFree: true
}
})
.when('/main', {
templateUrl: 'views/main.html',
controller: 'MainCtrl',
access: {
isFree: false
}
})
.otherwise({
redirectTo: '/'
});
});
})();
configTranslate.js:
'use strict';
(function() {
angular.module('wbApp')
.config(['$translateProvider',
function($translateProvider) {
$translateProvider.useStaticFilesLoader({
prefix: 'scripts/i18n/locale-',
suffix: '.json'
});
$translateProvider.preferredLanguage('en');
}]);
})();
karma.conf.js:
files = [
...
'app/bower_components/angular-translate/angular-translate.js',
'app/bower_components/angular-translate-loader-static-files/angular-translate-loader-static-files.js',
...
];
controller test:
'use strict';
describe('Controller: LoginCtrl', function() {
// load the controller's module
beforeEach(module('wbApp'));
var LoginCtrl, scope, location, httpMock, authUser;
// Initialize the controller and a mock scope
beforeEach(inject(function($controller, $rootScope, $location, $httpBackend, AuthUser) {
authUser = AuthUser;
location = $location;
httpMock = $httpBackend;
scope = $rootScope.$new();
LoginCtrl = $controller('LoginCtrl', {
$scope: scope
});
httpMock.when('GET', 'scripts/i18n/locale-en.json').passThrough();
}));
it(...);
...
});
if i add this in test controller, product same error:
httpMock.when('GET', 'scripts/i18n/locale-en.json').respond(200);
httpMock.flush();
or
httpMock.when('GET', 'scripts/i18n/locale-en.json').passThrough();
httpMock.flush();
i find this post How do I test controllers with Angular Translate initialized in App Config? but not helped me :/
I extensively use $httpBackend in my tests and it works fine, but in this case it is ineffective. If I comment the line:
$translateProvider.preferredLanguage('en');
obviously an error, if I add on the runtime (in my controllers)
$translate.uses(local);
I end up with the same error?
So I turn to the translation configuration (configTranslate.js) or at runtime is the same result:
Unexpected request: GET scripts/i18n/locale-en.json
Here is the syntax that I tested, either in a "beforeEach(inject(function(...});"
or in a test "it('...', function() {...});"
httpMock.expectGET('scripts/i18n/locale-en.json');
httpMock.when('GET', 'scripts/i18n/locale-en.json').passThrough();
httpMock.when('GET', 'scripts/i18n/locale-en.json').respond(data);
with at end
httpMock.flush();
I also tried a $ apply
httpMock.expectGET('scripts/i18n/locale-fr.json');
scope.$apply(function(){
$translate.uses('fr');
});
httpMock.flush();
nothing happens, Still this error is driving me crazy ..
If you have any suggestion
it's a known issue, please follow the documentation here: unit testing angular
The solution
Unfortunately, this issue is caused by the design of
angular-translate. To get around these errors, all we can do is to
overwrite our module configuration in our test suite, that it doesn't
use asynchronous loader at all. When there's no asynchronous loader,
there's no XHR and therefore no error.
So how do we overwrite our module configuration at runtime for our
test suite? When instantiating an angular module, we can always apply
a inline function which is executed as configuration function. This
configuration function can be used to overwrite the modules
configuration since we have access to all providers.
Using the $provide provider, we can build a custom loader factory,
which should then be used instead of the static files loader.
beforeEach(module('myApp', function ($provide, $translateProvider) {
$provide.factory('customLoader', function () {
// loader logic goes here
});
$translateProvider.useLoader('customLoader');
}));
Please read more in the above link provided.
We took the approach of ignoring the translation loader in unit tests, rather than being forced to modify each of the spec files.
One way to do it could be by separating the loader configuration to a separate file and then exclude it in karma.
So for example you can create a file app-i18n-loader.js (all other module configurations takes place in a different file):
angular
.module('myApp')
.config(loaderConfig);
loaderConfig.$inject = ['$translateProvider', '$translatePartialLoaderProvider'];
function loaderConfig($translateProvider, $translatePartialLoaderProvider) {
$translateProvider.useLoader('$translatePartialLoader', {
urlTemplate: 'assets/i18n/{part}/{lang}.json'
});
$translatePartialLoaderProvider.addPart('myApp');
}
And in your karma.conf.js exclude the file:
files: [
'bower_components/angular/angular.js',
'bower_components/angular-mocks/angular-mocks.js',
//...
'bower_components/angular-translate/angular-translate.js',
'bower_components/angular-translate-loader-partial/angular-translate-loader-partial.js',
'app/**/*.mdl.js',
'app/**/*.js'
],
exclude: [
'app/app-i18n-loader.js'
],
(Note: Answer edited to a solution that does not require grunt/gulp).
I wanted a solution,
which was not too hacky
which didn't require me to change my actual application code,
which wouldn't interfere with the ability to load additional modules
and most importantly which wouldn't require me to change every
single test.
This is what I ended up with:
// you need to load the 3rd party module first
beforeEach(module('pascalprecht.translate'));
// overwrite useStaticFilesLoader to get rid of request to translation file
beforeEach(module(function ($translateProvider) {
$translateProvider.useStaticFilesLoader = function () {
};
}));
Assuming you don't need the actual translations for your unit tests, this works great. Just put the beforeEach on a global level, preferably in it's own file inside the test folder. It will be executed before every other test then.
I encountered this problem with protractor tests. My solution was to mock translations like this:
angular.module('app')
.config(function ($translateProvider) {
$translateProvider.translations('en', {});
$translateProvider.preferredLanguage('en');
})
Now no language files are downloaded, no strings get translated and I just test against the string keys in specifications:
expect(element(by.css('#title')).getText()).toEqual('TITLE_TEXT');
Try putting to test method:
it('should ...', function() {
httpMock.when('GET', 'scripts/i18n/locale-en.json').respond({});
httpMock.expectGET('scripts/i18n/locale-en.json');
scope.resetForm(); // Action which fires a http request
httpMock.flush(); // Flush must be called after the http request
}
See examples from Angular docs
Please have a look at https://github.com/PascalPrecht/angular-translate/blob/master/test/unit/service/loader-static-files.spec.js as a reference.
In general, I would recommend using a standard translation loader for unit tests (without the hassle of http loadings) which means you can provide the labels with $translateProvider.translations(). Why? Because you do not have to test the remote loading functionality which is part of angular-translate project.
None of the solutions worked for me but I came with these solutions:
1) If you need to use scope.$apply(), or should deal with states in your test (after the $apply() the 2nd approach won't work), override your app's translations with the $translateProvider.translations() method, using a plugin to load JSON files
beforeEach(module(function ($translateProvider) {
$translateProvider.translations('en', readJSON('scripts/i18n/locale-en.json'));
}));
2) If your tested controller depends on the $translate service you can use a plugin to load JSON files and combine it with $httpBackend to load your locale file when angular-translate requests it.
beforeEach(inject(function (_$httpBackend_) {
$httpBackend = _$httpBackend_;
$httpBackend.whenGET('scripts/i18n/locale-en.json').respond(readJSON('scripts/i18n/locale-en.json'));
$httpBackend.flush();
})));
Note this should be below your beforeEach(module('myApp')); or you will get an $injector error.
I made a simple mock service for $translate
$translate=function (translation) {
return {
then: function (callback) {
var translated={};
translation.map(function (transl) {
translated[transl]=transl;
});
return callback(translated);
}
}
};
Usage example here : https://gist.github.com/dam1/5858bdcabb89effca457
I use this pattern.
ApplicationModule set regular angular-translate config.
test code load 'testModule' instead of 'applicationModule'
// application module .js
(function() {
'use strict';
angular
.module('applicationModule', [
'ngAnimate',
'ngResource',
'ui.router',
'pascalprecht.translate'
])
.config(['$stateProvider', '$urlRouterProvider', '$translateProvider', '$translatePartialLoaderProvider', config]);
function config($stateProvider, $urlRouterProvider, $translateProvider, $translatePartialLoaderProvider) {
// set routing ...
$translateProvider.useStaticFilesLoader({
prefix: 'i18n/locale-',
suffix: '.json'
});
$translateProvider.useMessageFormatInterpolation();
$translateProvider.fallbackLanguage(['en']);
$translateProvider
.registerAvailableLanguageKeys(['en', 'ko'], {
'en_US': 'en',
'ko_KR': 'ko'
})
.determinePreferredLanguage(navigator.browserLanguage);
$translateProvider.addInterpolation('$translateMessageFormatInterpolation');
$translateProvider.useSanitizeValueStrategy('escaped');
}
})();
// test.module.js
(function() {
'use strict';
angular
.module('testModule', ['applicationModule'])
.config(['$translateProvider', '$translatePartialLoaderProvider', config])
.run(['$httpBackend', run]);
function config($translateProvider, $translatePartialLoaderProvider) {
$translateProvider.useLoader('$translatePartialLoader', {
urlTemplate: 'i18n/locale-en.json'
});
$translatePartialLoaderProvider.addPart('applicationModule');
}
function run($httpBackend) {
$httpBackend.when('GET', 'i18n/locale-en.json').respond(200);
}
})();
// someDirective.spec.js
describe("a3Dashboard", function() {
beforeEach(module("testModule"))
var element, $scope;
beforeEach(inject(function($compile, $rootScope) {
$scope = $rootScope;
element = angular.element("<div>{{2 + 2}}</div>");
$compile(element)($rootScope)
}))
it('should equal 4', function() {
$scope.$digest();
expect(element.html()).toBe("4");
})
})
Late to the table with this, but I got round this by specifying that Karma simply serve the files as per this entry in karma.conf.js:
files: [
...
{pattern: 'scripts/i18n/*.json', included: false, served: true},
...
]
The 2016 answer for this is to preprocess your json into your tests and properly test translations work on your directives.
I use karma-ng-json2js-preprocessor. Follow all the steps to setup your karma.conf then in your test file, prepend the relevant file as a module, then set that information in $translateProvider.
beforeEach(module('myApp', '/l10n/english-translation.json'));
// Mock translations for this template
beforeEach(module(function($translateProvider, englishTranslation) {
$translateProvider.translations('en_us', englishTranslation);
$translateProvider.useSanitizeValueStrategy(null);
$translateProvider.preferredLanguage('en_us');
}));
Note according to the plugin, it uses your filename to generate a camelcased module name. You can play with the function inside the module's /lib but basically it remove all dashes but KEEPS underscores in a camelCase. So en_us becomes En_us.
You'll also need to tell your test that it is expecting that file as a GEt.
$httpBackend.expect('GET', '/l10n/english-translation.json').respond(200);