gistfile1.js

var module = angular.module('Test', []);

module.service('TestService', ['ServiceA', function(serviceA) {
}]);

module.service('ServiceA', function() {
    // First implementation of Service A
});

module.service('ServiceABis', function() {
    // Second implementation of Service A
});

Every time ServiceA is needed as a dependecy inject ServiceABis instead of ServiceA, for instance in TestService.

why would you not want serviceA?

var module = angular.module('Test', []);

module.service('TestService', ['ServiceA', function(serviceA) {
}]);

var ServiceA = window.location.search === '?IWantServiceABis' ? function() {
// Second implementation of Service A
} : function() {
// First implementation of Service A
};

module.service('ServiceA', ServiceA);

@ithinkdancan The issue came up when I was working without an Internet access and needed to request upon an API. I wanted to make a service returning fake data.

@christophehurpeau I think this would make our good friends cry too...