feat(ScrollSpy): Added ScrollSpy module

Added directives/components and service to implement ScrollSpy functionality

Author: edoparearyee

integration/e2e/app.e2e-spec.ts

@@ -2,6 +2,12 @@ import { browser, element, by } from 'protractor';
 
 describe('ScrollSpy Lib E2E Tests', function () {
 
+  const scrollToSection = (n: number) => {
+    const script = `window.scrollTo(0, (window.innerHeight * ${n - 1}) + 80)`;
+    browser.executeScript(script);
+    browser.sleep(100);
+  };
+
   beforeEach(() => browser.get(''));
 
   afterEach(() => {
@@ -14,4 +20,29 @@ describe('ScrollSpy Lib E2E Tests', function () {
     expect(element(by.css('[snScrollSpy]')).isPresent()).toBeTruthy();
   });
 
+  it('should add active class to sections', () => {
+    expect(element(by.css('[href="#section1"].active')).isPresent()).toBeTruthy();
+    expect(element(by.css('[href="#section2"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section3"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section4"].active')).isPresent()).toBeFalsy();
+
+    scrollToSection(2);
+    expect(element(by.css('[href="#section1"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section2"].active')).isPresent()).toBeTruthy();
+    expect(element(by.css('[href="#section3"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section4"].active')).isPresent()).toBeFalsy();
+
+    scrollToSection(3);
+    expect(element(by.css('[href="#section1"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section2"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section3"].active')).isPresent()).toBeTruthy();
+    expect(element(by.css('[href="#section4"].active')).isPresent()).toBeFalsy();
+
+    scrollToSection(4);
+    expect(element(by.css('[href="#section1"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section2"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section3"].active')).isPresent()).toBeFalsy();
+    expect(element(by.css('[href="#section4"].active')).isPresent()).toBeTruthy();
+  });
+
 });