chai-as-promised erroneously passes tests - angularjs

Question

I'm trying to write tests for a method that returns an angular promise ($q library).
I'm at a loss. I'm running tests using Karma, and I need to figure out how to confirm that the AccountSearchResult.validate() function returns a promise, confirm whether the promise was rejected or not, and inspect the object that is returned with the promise.
For example, the method being tested has the following (simplified):
.factory('AccountSearchResult', ['$q',
function($q) {
return {
validate: function(result) {
if (!result.accountFound) {
return $q.reject({
message: "That account or userID was not found"
});
}
else {
return $q.when(result);
}
}
};
}]);
I thought I could write a test like this:
it("it should return an object with a message property", function () {
promise = AccountSearchResult.validate({accountFound:false});
expect(promise).to.eventually.have.property("message"); // PASSES
});
That passes, but so does this (erroneously):
it("it should return an object with a message property", function () {
promise = AccountSearchResult.validate({accountFound:false});
expect(promise).to.eventually.have.property("I_DONT_EXIST"); // PASSES, should fail
});
I am trying to use the chai-as-promised 'eventually', but all my tests pass with false positives:
it("it should return an object", function () {
promise = AccountSearchResult.validate();
expect(promise).to.eventually.be.an('astronaut');
});
will pass. In looking at docs and SO questions, I have seen examples such as:
expect(promise).to.eventually.to.equal('something');
return promise.should.eventually.equal('something');
expect(promise).to.eventually.to.equal('something', "some message about expectation.");
expect(promise).to.eventually.to.equal('something').notify(done);
return assert.becomes(promise, "something", "message about assertion");
wrapping expectation in runs() block
wrapping expectation in setTimeout()
Using .should gives me Cannot read property 'eventually' of undefined. What am I missing?

Answer 1

#runTarm 's suggestions were both spot on, as it turns out. I believe that the root of the issue is that angular's $q library is tied up with angular's $digest cycle. So while calling $apply works, I believe that the reason it works is because $apply ends up calling $digest anyway. Typically I've thought of $apply() as a way to let angular know about something happening outside its world, and it didn't occur to me that in the context of testing, resolving a $q promise's .then()/.catch() might need to be pushed along before running the expectation, since $q is baked into angular directly. Alas.
I was able to get it working in 3 different ways, one with runs() blocks (and $digest/$apply), and 2 without runs() blocks (and $digest/$apply).
Providing an entire test is probably overkill, but in looking for the answer to this I found myself wishing people had posted how they injected / stubbed / setup services, and different expect syntaxes, so I'll post my entire test.
describe("AppAccountSearchService", function () {
var expect = chai.expect;
var $q,
authorization,
AccountSearchResult,
result,
promise,
authObj,
reasonObj,
$rootScope,
message;
beforeEach(module(
'authorization.services', // a dependency service I need to stub out
'app.account.search.services' // the service module I'm testing
));
beforeEach(inject(function (_$q_, _$rootScope_) {
$q = _$q_; // native angular service
$rootScope = _$rootScope_; // native angular service
}));
beforeEach(inject(function ($injector) {
// found in authorization.services
authObj = $injector.get('authObj');
authorization = $injector.get('authorization');
// found in app.account.search.services
AccountSearchResult = $injector.get('AccountSearchResult');
}));
// authObj set up
beforeEach(inject(function($injector) {
authObj.empAccess = false; // mocking out a specific value on this object
}));
// set up spies/stubs
beforeEach(function () {
sinon.stub(authorization, "isEmployeeAccount").returns(true);
});
describe("AccountSearchResult", function () {
describe("validate", function () {
describe("when the service says the account was not found", function() {
beforeEach(function () {
result = {
accountFound: false,
accountId: null
};
AccountSearchResult.validate(result)
.then(function() {
message = "PROMISE RESOLVED";
})
.catch(function(arg) {
message = "PROMISE REJECTED";
reasonObj = arg;
});
// USING APPLY... this was the 'magic' I needed
$rootScope.$apply();
});
it("should return an object", function () {
expect(reasonObj).to.be.an.object;
});
it("should have entered the 'catch' function", function () {
expect(message).to.equal("PROMISE REJECTED");
});
it("should return an object with a message property", function () {
expect(reasonObj).to.have.property("message");
});
// other tests...
});
describe("when the account ID was falsey", function() {
// example of using runs() blocks.
//Note that the first runs() content could be done in a beforeEach(), like above
it("should not have entered the 'then' function", function () {
// executes everything in this block first.
// $rootScope.apply() pushes promise resolution to the .then/.catch functions
runs(function() {
result = {
accountFound: true,
accountId: null
};
AccountSearchResult.validate(result)
.then(function() {
message = "PROMISE RESOLVED";
})
.catch(function(arg) {
reasonObj = arg;
message = "PROMISE REJECTED";
});
$rootScope.$apply();
});
// now that reasonObj has been populated in prior runs() bock, we can test it in this runs() block.
runs(function() {
expect(reasonObj).to.not.equal("PROMISE RESOLVED");
});
});
// more tests.....
});
describe("when the account is an employee account", function() {
describe("and the user does not have EmployeeAccess", function() {
beforeEach(function () {
result = {
accountFound: true,
accountId: "160515151"
};
AccountSearchResult.validate(result)
.then(function() {
message = "PROMISE RESOLVED";
})
.catch(function(arg) {
message = "PROMISE REJECTED";
reasonObj = arg;
});
// digest also works
$rootScope.$digest();
});
it("should return an object", function () {
expect(reasonObj).to.be.an.object;
});
// more tests ...
});
});
});
});
});
Now that I know the fix, it is obvious from reading the $q docs under the testing section, where it specifically says to call $rootScope.apply(). Since I was able to get it working with both $apply() and $digest(), I suspect that $digest is really what needs to be called, but in keeping with the docs, $apply() is probably 'best practice'.
Decent breakdown on $apply vs $digest.
Finally, the only mystery remaining to me is why the tests were passing by default. I know I was getting to the expectations (they were being run). So why would expect(promise).to.eventually.be.an('astronaut'); succeed? /shrug
Hope that helps. Thanks for the push in the right direction.