Angular Tests always fail on $logProvider when getting constants in tests - angularjs

Question

Very new to Angular testing... using 1.3.0.rc0. To get started I'm trying to do something simple: get the value of a constant I set. Within a config.js, I have the following:
(function () {
'use strict';
var app = angular.module('app');
// create app configuration
var appConfig = {
version = '0.0.1.0',
debugMode = true
};
app.constant('config', appConfig);
app.config([function ($logProvider, config) {
// set the debugging setting of the app > same setting for the app
if ($logProvider.debugEnabled) {
$logProvider.debugEnabled(config.debugMode);
}
}]);
})();
I'm tried numerous things to write my tests (using jasmine & karma), but I keep getting an error that:
Error: [$injector:modulerr] Failed to instantiate module app due to:
TypeError: 'undefined' is not an object (evaluating '$logProvider.debugEnabled').
I get that this was a bug a while ago in the angular-mocks.js file but has since been resolved. Regardless, no matter the test I write, it doesn't work. Here's what i'm working with now, knowing that there are issues with it.
'use strict';
describe('config.js', function () {
var logProvider;
beforeEach(module(inject(function ($log) {
logProvider = $log;
})));
beforeEach(module('app', logProvider));
it('should set the config constant to the app global configuration settings', function () {
var $injector = angular.injector(['ng', 'app']);
var settings = $injector.get('config');
//var settings = inject(config);
expect(settings.debugMode).toBe(true);
});
});
Am I doing this right? If so, is there no way to get around the test issue with $logProvider?

Answer 1

There is much to learn about how modules work in Angular, especially under testing with ngMocks. I'll try to be brief.
One always begins by calling module (from ngMocks) one (or more times) to build up the module "cookbook" for a test run.
In any of these module calls you have an opportunity to access and stash away a previously defined provider.
The first time you call inject (from ngMocks) in a given test path, the module "cookbook" is "baked" for that path and the injector is populated based on recipes in that "cookbook".
Subsequent calls to module are irrelevant. Your expression beforeEach(module('app', logProvider)); executes too late (even if it did what you wanted, which it would not).
In fact, I'm surprised that you didn't get the error: "Error: Injector already created, can not register a module!".
inject always returns the thing created by the provider, never the provider itself. Your first beforeEach ...
beforeEach(module(inject(function ($log) {
logProvider = $log;
})));
... actually sets logProvider to the $log service, not the $logProvider.
Does this help?
Here is a sample from my forthcoming course on Ng testing that shows how to access a provider (in this case, the $logProvider). It was inspired by your question.
First, the config2 constant (I already had a value called config:
// my sample application module definition is called 'basics'
var basics = angular.module('basics', []);
/* define 'config2' constant - which is available in Ng's config phase */
basics.constant('config2', {
debugMode: true
});
// use constant in config phase
basics.config(function ($logProvider, config2) {
$logProvider.debugEnabled(config2.debugMode);
})
Now the spec (using Mocha and Chai):
describe('Basics - constant:', function() {
'use strict';
beforeEach(module('basics'));
// other stuff
describe("the $logProvider", function(){
var configConstant;
var $log;
var $logProvider;
beforeEach(module(
// Could combine with module('basics') definition in outer describe
// but only need it here in this describe
// This module definition function has access to any previously defined provider
// which in this case is any provider defined in ng, ngMocks, or basics
function( _$logProvider_) {
$logProvider = _$logProvider_;
}
));
// inject triggers injector creation; module definition now "baked"
beforeEach(inject(function(config2, _$log_){
configConstant = config2;
$log = _$log_;
}));
it("is accessible via the module function", function(){
expect($logProvider).to.exist;
});
it("is not the same as the log service", function(){
expect($logProvider).not.to.equal($log);
});
it("has same debugEnabled value as config2.debugMode", function(){
expect($logProvider.debugEnabled()).to.equal(configConstant.debugMode);
});
});
});