I am having a problem where my code mixes ES6 Promises with Angular promises, and it works in production by I cannot write unit tests that pass.
This code snippet demonstrates two instances where Jasmine unit tests will fail, but the code works fine in production:
// An angular $q promise
var f1 = function() {
return $q(function(resolve, reject) {
resolve('This is function 1!');
});
}
// An ES6 promise
var f2 = function() {
return new Promise(function(resolve, reject) {
resolve('This is function 2!');
});
}
// An angular $q.all() promise, attempting to resolve a $q and ES6 promise.
var s1 = function() {
return $q.all([f1(), f2()]).then(function() {
return '$q resolved both promises!'
});
}
// An ES6 promise attempting to resolve a $q and an ES6 promise.
var s2 = function() {
return Promise.all([f1(), f2()]).then(function() {
return 'ES6 resolved both promises!'
});
}
The tests look like:
describe('Testing mixed ES6 promises and Angular $q', function() {
var $scope = null;
var service = null;
//you need to indicate your module in a test
beforeEach(module('plunker'));
beforeEach(inject(function($rootScope, _testService_) {
$scope = $rootScope.$new();
service = _testService_;
}));
afterEach(function() {
});
it('should resolve f1', function(done) {
var t1 = service.f1();
t1.then(function() {
done();
});
$scope.$apply();
});
it('should resolve f2', function(done) {
var t1 = service.f1();
t1.then(function() {
done();
});
$scope.$apply();
});
it('should resolve s1', function(done) {
var t1 = service.s1();
t1.then(function() {
done();
});
$scope.$apply();
});
it('should resolve s2', function(done) {
var t1 = service.s2();
t1.then(function() {
done();
});
$scope.$apply();
});
});
This Plunker has a working demonstration: http://plnkr.co/edit/xhRc7O
Notice that the first 2 tests pass because they are straightforward ES6 or $q promises.
Then notice that every other tests fails because I mix ES6 and $q promises in different ways.
Finally, notice that in the controller I demonstrate that two FAILING tests do in fact work in production.
Why does Angular not let me mix ES6 and $q promises in my tests, yet have no problems in production code?