Leaflet/spec/suites/core/EventsSpec.js

describe('Events', function () {

	describe('#fireEvent', function () {

		it('fires all listeners added through #addEventListener', function () {
			var obj = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    spy3 = sinon.spy(),
			    spy4 = sinon.spy(),
			    spy5 = sinon.spy(),
			    spy6 = sinon.spy();

			obj.addEventListener('test', spy1);
			obj.addEventListener('test', spy2);
			obj.addEventListener('other', spy3);
			obj.addEventListener({test: spy4, other: spy5});
			// obj.addEventListener({'test other': spy6 });

			expect(spy1.called).to.be(false);
			expect(spy2.called).to.be(false);
			expect(spy3.called).to.be(false);
			expect(spy4.called).to.be(false);
			expect(spy5.called).to.be(false);
			// expect(spy6.called).to.be(false);

			obj.fireEvent('test');

			expect(spy1.called).to.be(true);
			expect(spy2.called).to.be(true);
			expect(spy3.called).to.be(false);
			expect(spy4.called).to.be(true);
			expect(spy5.called).to.be(false);
			// expect(spy6.called).to.be(true);
			// expect(spy6.callCount).to.be(1);
		});

		it('fires all listeners in the order they are added', function () {
			var obj = new L.Evented(),
			    ctx1 = new L.Class(),
			    ctx2 = new L.Class(),
			    count = {one: 0, two: 0, three: 0, four: 0};

			function listener1(e) {
				count.one++;
				expect(count.two).to.eql(0);
			}

			function listener2(e) {
				count.two++;
				expect(count.one).to.eql(1);
				expect(count.three).to.eql(0);
				if (count.two === 1) {
					expect(this).to.eql(ctx2);
				} else if (count.two === 2) {
					expect(this).to.eql(ctx1);
				} else {
					expect(this).to.eql(obj);
				}
			}

			function listener3(e) {
				count.three++;
				expect(count.two).to.eql(3);
				expect(count.four).to.eql(0);
				if (count.three === 1) {
					expect(this).to.eql(ctx1);
				} else if (count.three === 2) {
					expect(this).to.eql(ctx2);
				}
			}

			function listener4(e) {
				count.four++;
				expect(count.three).to.eql(2);
			}

			obj.on('test', listener1, ctx1);
			obj.on('test', listener2, ctx2);
			obj.on('test', listener2, ctx1);  // Same listener but with different context.
			obj.on('test', listener2);  // Same listener but without context.
			obj.on('test', listener3, ctx1);
			obj.on('test', listener3, ctx2);
			obj.on('test', listener4, ctx2);

			obj.fireEvent('test');

			expect(count.one).to.be(1);
			expect(count.two).to.be(3);
			expect(count.three).to.be(2);
			expect(count.four).to.be(1);
		});

		it('provides event object to listeners and executes them in the right context', function () {
			var obj = new L.Evented(),
			    obj2 = new L.Evented(),
			    obj3 = new L.Evented(),
			    obj4 = new L.Evented(),
			    foo = {};

			function listener1(e) {
				expect(e.type).to.eql('test');
				expect(e.target).to.eql(obj);
				expect(this).to.eql(obj);
				expect(e.baz).to.eql(1);
			}

			function listener2(e) {
				expect(e.type).to.eql('test');
				expect(e.target).to.eql(obj2);
				expect(this).to.eql(foo);
				expect(e.baz).to.eql(2);
			}

			function listener3(e) {
				expect(e.type).to.eql('test');
				expect(e.target).to.eql(obj3);
				expect(this).to.eql(obj3);
				expect(e.baz).to.eql(3);
			}

			function listener4(e) {
				expect(e.type).to.eql('test');
				expect(e.target).to.eql(obj4);
				expect(this).to.eql(foo);
				expect(e.baz).to.eql(4);
			}

			obj.addEventListener('test', listener1);
			obj2.addEventListener('test', listener2, foo);
			obj3.addEventListener({test: listener3});
			obj4.addEventListener({test: listener4}, foo);

			obj.fireEvent('test', {baz: 1});
			obj2.fireEvent('test', {baz: 2});
			obj3.fireEvent('test', {baz: 3});
			obj4.fireEvent('test', {baz: 4});
		});

		it('calls no listeners removed through #removeEventListener', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    spy2 = sinon.spy(),
			    spy3 = sinon.spy(),
			    spy4 = sinon.spy(),
			    spy5 = sinon.spy();

			obj.addEventListener('test', spy);
			obj.removeEventListener('test', spy);

			obj.fireEvent('test');

			expect(spy.called).to.be(false);

			obj.addEventListener('test2', spy2);
			obj.addEventListener('test2', spy3);
			obj.removeEventListener('test2');

			obj.fireEvent('test2');

			expect(spy2.called).to.be(false);
			expect(spy3.called).to.be(false);

			obj.addEventListener('test3', spy4);
			obj.addEventListener('test4', spy5);
			obj.removeEventListener({
				test3: spy4,
				test4: spy5
			});

			obj.fireEvent('test3');
			obj.fireEvent('test4');

			expect(spy4.called).to.be(false);
			expect(spy5.called).to.be(false);
		});

		it('can handle calls to #removeEventListener on objects with no registered event listeners', function () {
			var obj = new L.Evented();
			var removeNonExistentListener = function () {
				obj.removeEventListener('test');
			};
			expect(removeNonExistentListener).to.not.throwException();
		});

		// added due to context-sensitive removeListener optimization
		it('fires multiple listeners with the same context with id', function () {
			var obj = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    foo = {};

			L.Util.stamp(foo);

			obj.addEventListener('test', spy1, foo);
			obj.addEventListener('test', spy2, foo);

			obj.fireEvent('test');

			expect(spy1.called).to.be(true);
			expect(spy2.called).to.be(true);
		});

		it('removes listeners with stamped contexts', function () {
			var obj = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    foo = {};

			L.Util.stamp(foo);

			obj.addEventListener('test', spy1, foo);
			obj.addEventListener('test', spy2, foo);

			obj.removeEventListener('test', spy1, foo);

			obj.fireEvent('test');

			expect(spy1.called).to.be(false);
			expect(spy2.called).to.be(true);
		});

		it('removes listeners with a stamp originally added without one', function () {
			var obj = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    foo = {};

			obj.addEventListener('test', spy1, foo);
			L.Util.stamp(foo);
			obj.addEventListener('test', spy2, foo);

			obj.removeEventListener('test', spy1, foo);
			obj.removeEventListener('test', spy2, foo);

			obj.fireEvent('test');

			expect(spy1.called).to.be(false);
			expect(spy2.called).to.be(false);
		});

		it('removes listeners with context == this and a stamp originally added without one', function () {
			var obj = new L.Evented(),
			    obj2 = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    spy3 = sinon.spy();

			obj.addEventListener('test', spy1, obj);
			L.Util.stamp(obj);
			obj.addEventListener('test', spy2, obj);
			obj.addEventListener('test', spy3, obj2); // So that there is a contextId based listener, otherwise removeEventListener will do correct behaviour anyway

			obj.removeEventListener('test', spy1, obj);
			obj.removeEventListener('test', spy2, obj);
			obj.removeEventListener('test', spy3, obj2);

			obj.fireEvent('test');

			expect(spy1.called).to.be(false);
			expect(spy2.called).to.be(false);
			expect(spy3.called).to.be(false);
		});

		it('doesnt lose track of listeners when removing non existent ones', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    spy2 = sinon.spy(),
			    foo = {},
			    foo2 = {};

			L.Util.stamp(foo);
			L.Util.stamp(foo2);

			obj.addEventListener('test', spy, foo2);

			obj.removeEventListener('test', spy, foo); // Decrements test_idx to 0, even though event listener isn't registered with foo's _leaflet_id
			obj.removeEventListener('test', spy, foo2);  // Doesn't get removed

			obj.addEventListener('test', spy2, foo);

			obj.fireEvent('test');

			expect(spy.called).to.be(false);
		});

		it('correctly removes all listeners if given no fn', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    foo = {},
			    foo2 = {},
			    foo3 = {};

			obj.addEventListener('test', spy, foo2);
			obj.addEventListener('test', spy, foo3);

			obj.removeEventListener('test'); // Removes both of the above listeners

			expect(obj.listens('test')).to.be(false);

			// Add and remove a listener
			obj.addEventListener('test', spy, foo2);
			obj.removeEventListener('test', spy, foo2);

			expect(obj.listens('test')).to.be(false);

			// Add and remove a listener without context
			obj.addEventListener('test', spy);
			obj.removeEventListener('test', spy);

			expect(obj.listens('test')).to.be(false);
		});

		it('makes sure an event is not triggered if a listener is removed during dispatch', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    spy2 = sinon.spy(),
			    spy3 = sinon.spy(),
			    foo = {};

			/* without context */
			obj.addEventListener('test', function () { obj.removeEventListener('test', spy); });
			obj.addEventListener('test', spy);
			obj.fireEvent('test');

			expect(spy.called).to.be(false);

			/* with context */
			obj.addEventListener('test2', function () { obj.removeEventListener('test2', spy2, foo); }, foo);
			obj.addEventListener('test2', spy2, foo);
			obj.fireEvent('test2');
		});

		it('makes sure an event is not triggered if all listeners are removed during dispatch', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.addEventListener('test', function () { obj.removeEventListener('test'); });
			obj.addEventListener('test', spy);
			obj.fire('test');

			expect(spy.called).to.be(false);
		});

		it('handles reentrant event firing', function () {
			var obj = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy();

			obj
				.addEventListener('test1', function () {
					obj.fire('test2');
				})
				.addEventListener('test2', spy1)
				.addEventListener('test1', function () {
					obj.removeEventListener('test1', spy2);
				})
				.addEventListener('test1', spy2);

			obj.fireEvent('test1');
			expect(spy1.called).to.be(true);
			expect(spy2.called).to.be(false);
		});

		it('can remove an event listener while firing', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			var removeSpy = function () {
				obj.removeEventListener('test', spy);
			};

			obj.addEventListener('test', spy);
			obj.addEventListener('test', removeSpy);

			obj.fire('test');

			obj.removeEventListener('test', removeSpy);

			expect(obj.listens('test')).to.be(false);
		});
	});

	describe('#on, #off & #fire', function () {

		it('works like #addEventListener && #removeEventListener', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.on('test', spy);
			obj.fire('test');

			expect(spy.called).to.be(true);

			obj.off('test', spy);
			obj.fireEvent('test');

			expect(spy.callCount).to.be.lessThan(2);
		});

		it('does not override existing methods with the same name', function () {
			var spy1 = sinon.spy(),
			    spy2 = sinon.spy(),
			    spy3 = sinon.spy();

			var Klass = L.Evented.extend({
				on: spy1,
				off: spy2,
				fire: spy3
			});

			var obj = new Klass();

			obj.on();
			expect(spy1.called).to.be(true);

			obj.off();
			expect(spy2.called).to.be(true);

			obj.fire();
			expect(spy3.called).to.be(true);
		});

		it('does not add twice the same function', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			/* register without context */
			obj.on("test", spy);
			obj.on("test", spy);

			/* Should be called once */
			obj.fire("test");

			expect(spy.callCount).to.eql(1);
		});
	});

	describe("#clearEventListeners", function () {
		it("clears all registered listeners on an object", function () {
			var spy = sinon.spy(),
			    obj = new L.Evented(),
			    otherObj = new L.Evented();

			obj.on('test', spy, obj);
			obj.on('testTwo', spy);
			obj.on('test', spy, otherObj);
			obj.off();

			obj.fire('test');

			expect(spy.called).to.be(false);
		});
	});

	describe('#once', function () {
		it('removes event listeners after first trigger', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.once('test', spy, obj);
			obj.fire('test');

			expect(spy.called).to.be(true);

			obj.fire('test');

			expect(spy.callCount).to.be.lessThan(2);
		});

		it('works with an object hash', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    otherSpy = sinon.spy();

			obj.once({
				'test': spy,
				otherTest: otherSpy
			}, obj);

			obj.fire('test');
			obj.fire('otherTest');

			expect(spy.called).to.be(true);
			expect(otherSpy.called).to.be(true);

			obj.fire('test');
			obj.fire('otherTest');

			expect(spy.callCount).to.be.lessThan(2);
			expect(otherSpy.callCount).to.be.lessThan(2);
		});

		it("doesn't call listeners to events that have been removed", function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.once('test', spy, obj);
			obj.off('test', spy, obj);

			obj.fire('test');

			expect(spy.called).to.be(false);
		});

		it('works if called from a context that doesnt implement #Events', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy(),
			    foo = {};

			obj.once('test', spy, foo);

			obj.fire('test');

			expect(spy.called).to.be(true);
		});
	});

	describe('addEventParent && removeEventParent', function () {
		it('makes the object propagate events with to the given one if fired with propagate=true', function () {
			var obj = new L.Evented(),
			    parent1 = new L.Evented(),
			    parent2 = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy();

			parent1.on('test', spy1);
			parent2.on('test', spy2);

			obj.addEventParent(parent1).addEventParent(parent2);

			obj.fire('test');

			expect(spy1.called).to.be(false);
			expect(spy2.called).to.be(false);

			obj.fire('test', null, true);

			expect(spy1.called).to.be(true);
			expect(spy2.called).to.be(true);

			obj.removeEventParent(parent1);

			obj.fire('test', null, true);

			expect(spy1.callCount).to.be(1);
			expect(spy2.callCount).to.be(2);
		});

		it('can fire event where child has no listeners', function () {
			var obj = new L.Evented(),
			    parent = new L.Evented(),
			    spy1 = sinon.spy(),
			    spy2 = sinon.spy();

			/* register without context */
			obj.on('test', spy1);
			parent.on('test2', spy2);

			obj.addEventParent(parent);

			/* Should be called once */
			obj.fire('test2', null, true);

			expect(spy1.callCount).to.eql(0);
			expect(spy2.callCount).to.eql(1);
		});
	});

	describe('#listens', function () {
		it('is false if there is no event handler', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			expect(obj.listens('test')).to.be(false);
		});

		it('is true if there is an event handler', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.on('test', spy);
			expect(obj.listens('test')).to.be(true);
		});

		it('is false if event handler has been removed', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.on('test', spy);
			obj.off('test', spy);
			expect(obj.listens('test')).to.be(false);
		});

		it('changes for a "once" handler', function () {
			var obj = new L.Evented(),
			    spy = sinon.spy();

			obj.once('test', spy);
			expect(obj.listens('test')).to.be(true);

			obj.fire('test');
			expect(obj.listens('test')).to.be(false);
		});
	});

});