adding tests

Author: jscottsmith

__tests__/ParallaxController.test.js

@@ -0,0 +1,52 @@
+import { ParallaxController } from 'react-scroll-parallax';
+
+const addEventListener = window.addEventListener;
+const removeEventListener = window.removeEventListener;
+
+describe('Expect the ParallaxController', () => {
+
+    afterEach(() => {
+        window.addEventListener = addEventListener;
+        window.removeEventListener = removeEventListener;
+    });
+
+    it('to return an instance on init', () => {
+        const instance = ParallaxController.init();
+        expect(instance).toBeInstanceOf(ParallaxController);
+    });
+
+    it('to return an existing instance from the window on init', () => {
+        window.ParallaxController = 'foo';
+        const instance = ParallaxController.init();
+        expect(instance).toBe('foo');
+        window.ParallaxController = undefined;
+    });
+
+    it('to throw on init if there\'s no window');
+
+    it('to add listeners when init', () => {
+        window.addEventListener = jest.fn();
+        const instance = ParallaxController.init();
+
+        expect(window.addEventListener.mock.calls[1]).toEqual(
+            expect.arrayContaining(['scroll', expect.any(Function), false])
+        );
+        expect(window.addEventListener.mock.calls[2]).toEqual(
+            expect.arrayContaining(['resize', expect.any(Function), false])
+        );
+    });
+
+    it('to remove listeners when destroyed', () => {
+        window.removeEventListener = jest.fn();
+        const instance = ParallaxController.init();
+
+        instance.destroy();
+        expect(window.removeEventListener.mock.calls[0]).toEqual(
+            expect.arrayContaining(['scroll', expect.any(Function), false])
+        );
+        expect(window.removeEventListener.mock.calls[1]).toEqual(
+            expect.arrayContaining(['resize', expect.any(Function), false])
+        );
+        expect(window.ParallaxController).toBe(null);
+    });
+});

__tests__/testForPassiveScroll.test.js

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+import { testForPassiveScroll } from 'utils';
+
+const addEventListener = window.addEventListener;
+const removeEventListener = window.removeEventListener;
+
+describe('Expect the testForPassiveScroll function', () => {
+
+    afterEach(() => {
+        window.addEventListener = addEventListener;
+        window.removeEventListener = removeEventListener;
+    });
+
+    it('to return a boolean', () => {
+        const bool = testForPassiveScroll();
+        expect(bool).toBe(false)
+    });
+
+    it('to add and remove a test listener', () => {
+        window.addEventListener = jest.fn();
+        window.removeEventListener = jest.fn();
+        const bool = testForPassiveScroll();
+        expect(window.addEventListener.mock.calls[0]).toEqual(
+            expect.arrayContaining(['test', null, expect.any(Object)])
+        );
+        expect(window.removeEventListener.mock.calls[0]).toEqual(
+            expect.arrayContaining(['test', null, expect.any(Object)])
+        );
+    });
+});