Exploring a new service, Service A, with various functionalities:
The snippet of application code is as follows:
angular.module('app').factory('ServiceA', function() {
var ServiceA = {
_retryItem: null,
retryItem: function(type, data) {
ServiceA._retryItem = {
type: type,
data: data
};
return this;
},
clear: function() {
ServiceA._retryItem = null;
return this;
},
start: function(options, retryFn) {
ServiceA.clear();
ServiceA.retryItem('action', {url: '/my-url', options: options, retryFn: retryFn});
}
};
return ServiceA;
});
To test the "start" function, two options are available:
1) Utilize the real functions clear and retryItem:
...
describe('...', function() {
var options, retryFn;
beforeEach(function() {
options = {};
retryFn = function() {};
});
it('...', function() {
ServiceA.start(options, retryFn);
expect(ServiceA._retryItem).toEqual({type: 'action', data: {url: '/my-url', options: options, retryFn: retryFn});
});
});
2) Mock both functions clear and retryItem:
...
describe('...', function() {
var options, retryFn;
beforeEach(function() {
options = {};
retryFn = function() {};
spyOn(ServiceA, 'clear');
spyOn(ServiceA, 'retryItem');
});
it('...', function() {
ServiceA.start(options, retryFn);
expect(ServiceA.clear).toHaveBeenCalled();
expect(ServiceA.retryItem).toHaveBeenCalledWith('action', {url: '/my-url', options: options, retryFn: retryFn});
});
});
Which method should be adopted? In unit testing, the focus is on testing the specific unit, here being the "start" function. The other functions like clear and retryItem can be mocked to ensure efficient and isolated testing, offering greater control over the test scenarios.