Ember has a guide on how to do that here. I'll put the code here in case the guide changes.
Given this component:
App.MyFooComponent = Ember.Component.extend({
layout:Ember.Handlebars.compile("<button {{action 'doSomething'}}></button>"),
actions: {
doSomething: function() {
this.sendAction('internalAction');
}
}
});
You would test the action like this:
moduleForComponent('my-foo', 'MyFooComponent');
test('trigger external action when button is clicked', function() {
// tell our test to expect 1 assertion
expect(1);
// component instance
var component = this.subject();
// component dom instance
var $component = this.append();
var targetObject = {
externalAction: function() {
// we have the assertion here which will be
// called when the action is triggered
ok(true, 'external Action was called!');
}
};
// setup a fake external action to be called when
// button is clicked
component.set('internalAction', 'externalAction');
// set the targetObject to our dummy object (this
// is where sendAction will send its action to)
component.set('targetObject', targetObject);
// click the button
click('button');
});