Events.on unit tests

test/unit/core/Events.spec.js

@@ -0,0 +1,83 @@
+const Events = require("../../../src/core/Events");
+
+describe('Events.on', () => {
+	it('should be able to add callback to object under event name', () => {
+		// Arrange
+		let object = {};
+        let eventNames = 'testEvent';
+        let callback = () => { return true; };
+
+		// Act
+		Events.on(object, eventNames, callback);
+		
+		// Assert
+		expect(object.events[eventNames][0]).toEqual(callback);
+	});
+
+	it('returned callback should be the same ass passed callback', () => {
+		// Arrange
+		let object = {};
+        let eventNames = 'testEvent';
+        let callback = () => { return true; };
+
+		// Act
+		let result = Events.on(object, eventNames, callback);
+		
+		// Assert
+		expect(result).toEqual(callback);
+	});
+
+	it('should be able to add callback to object with existing events under event name', () => {
+		// Arrange
+		let object = {};
+        let eventNames = 'testEvent';
+		object.events = {};
+		object.events[eventNames] = [ () => { return false;  } ]; 
+		let callback = () => { return true; };
+
+		// Act
+		Events.on(object, eventNames, callback);
+
+		// Assert
+		expect(object.events[eventNames][1]).toEqual(callback);
+	});
+
+	it('should be able to add un undefinded callback to object under event name', () => {
+		// Arrange
+		let object = {};
+        let eventNames = 'testEvent';
+        let callback = undefined;
+
+		// Act
+		Events.on(object, eventNames, callback);
+		
+		// Assert
+		expect(object.events[eventNames][0]).toEqual(callback);
+	});
+
+	it('should not be able to add callback to object under undefined event name', () => {
+		// Arrange
+		let object = {};
+        let eventNames = undefined;
+        let callback = () => { return true; };
+
+		// Act
+		let result = () => Events.on(object, eventNames, callback);
+		
+		// Assert
+		expect(result).toThrow(/^Cannot .* properties of undefined \(.* '.*'\)$/);
+	});
+
+	it('should be not able to add callback to undefined object under event name', () => {
+		// Arrange
+		let object = undefined;
+        let eventNames = 'testEvent';
+        let callback = () => { return true; };
+
+		// Act
+		let result = () => Events.on(object, eventNames, callback);
+		
+		// Assert
+		expect(result).toThrow(/^Cannot .* properties of undefined \(.* '.*'\)$/);
+	});
+});