Add another events test and fix from @iirvine

Author: danzel

spec/suites/core/EventsSpec.js

@@ -181,6 +181,27 @@ describe('Events', function() {
 			expect(spy1).not.toHaveBeenCalled();
 			expect(spy2).not.toHaveBeenCalled();
 		});
+		it('doesnt lose track of listeners when removing non existent ones', function () {
+			var obj = new Klass(),
+			    spy = jasmine.createSpy(),
+			    spy2 = jasmine.createSpy(),
+			    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).not.toHaveBeenCalled();
+		});
 	});
 
 	describe('#on, #off & #fire', function() {

src/core/Events.js

@@ -99,7 +99,7 @@ L.Mixin.Events = {
 					}
 				}
 
-				if (contextId && listeners.length === 0 && events[objKey]) {
+				if (contextId && listeners.length === 0 && events[objKey] && events[objKey][contextId]) {
 					objLenKey = objKey + '_len';
 					delete events[objKey][contextId];
 					events[objLenKey] = (events[objLenKey] || 1) - 1;