diff --git a/src/js/modules/webslides.js b/src/js/modules/webslides.js
index 19df7e0..a47affd 100644
--- a/src/js/modules/webslides.js
+++ b/src/js/modules/webslides.js
@@ -358,7 +358,7 @@ export default class WebSlides {
    * @private
    */
   isValidIndexSlide_(i) {
-    return i >= 0 && i < this.maxSlide_;
+    return typeof i === 'number' && i >= 0 && i < this.maxSlide_;
   }
 
   /**
@@ -379,6 +379,7 @@ export default class WebSlides {
     // Keeping the order
     if (slideNumber !== 0) {
       let i = 0;
+
       while(i < slideNumber) {
         this.slides[i].moveAfterLast();
         i++;
diff --git a/test/modules/webslides.test.js b/test/modules/webslides.test.js
index 29dced6..fdf0733 100644
--- a/test/modules/webslides.test.js
+++ b/test/modules/webslides.test.js
@@ -1,79 +1,379 @@
 import WebSlides from '../../src/js/modules/webslides';
+import Slide from '../../src/js/modules/slide';
+import DOM from '../../src/js/utils/dom';
 
 jest.useFakeTimers();
 
-beforeAll(() => {
+let ws;
+let webslides;
+
+beforeEach(() => {
   const slides =
     '<section class="slide"><div class="content">Content</section>'.repeat(20);
   document.body.innerHTML =
       `<div id="webslides">${slides}<div id="other"></div></div>`;
+
+  ws = document.getElementById('webslides');
+  webslides = new WebSlides();
 });
 
-test('WebSlides utility', () => {
-  let webslides;
-  const ws = document.getElementById('webslides');
-  const change = jest.fn();
+afterEach(() => {
+  document.body.innerHTML = '';
+  location.hash = '';
+});
+
+test('Should throw if no element is found with webslides id', () => {
+  document.body.innerHTML = '';
+
   expect(() => {
     ws.setAttribute('id', '');
-    webslides = new WebSlides();
-  }).toThrow();
+    new WebSlides();
+  }).toThrow('Couldn\'t find the webslides container!');
+});
 
-  ws.setAttribute('id', 'webslides');
-  expect(() => {
-    webslides = new WebSlides();
-  }).not.toThrow();
-  webslides.el.addEventListener('ws:slide-change', change);
-  expect(document.getElementById('other')).toBe(null);
-  expect(webslides.slides.length)
-      .toBe(document.querySelectorAll('#webslides .slide').length);
-  webslides.slides.forEach(slide => {
-    expect(typeof slide).toBe('object');
+test('Should have correct properties', () => {
+  expect(webslides.isMoving).toBe(false);
+  expect(webslides.slides.length).toBe(20);
+  expect(webslides.currentSlideI_).toBe(0);
+  expect(webslides.currentSlide_).toBe(webslides.slides[0]);
+  expect(webslides.maxSlide_).toBe(20);
+  expect(webslides.isVertical).toBe(false);
+  expect(webslides.initialised).toBe(true);
+
+  expect(webslides.slides[0]).toBeInstanceOf(Slide);
+
+  // Plugins
+  expect(webslides.plugins.autoslide).toBeDefined();
+  expect(webslides.plugins.clickNav).toBeDefined();
+  expect(webslides.plugins.grid).toBeDefined();
+  expect(webslides.plugins.hash).toBeDefined();
+  expect(webslides.plugins.keyboard).toBeDefined();
+  expect(webslides.plugins.nav).toBeDefined();
+  expect(webslides.plugins.scroll).toBeDefined();
+  expect(webslides.plugins.touch).toBeDefined();
+  expect(webslides.plugins.video).toBeDefined();
+  expect(webslides.plugins.youtube).toBeDefined();
+  expect(webslides.plugins.zoom).toBeDefined();
+
+  // Options
+  expect(webslides.options.autoslide).toBe(false);
+  expect(webslides.options.changeOnClick).toBe(false);
+  expect(webslides.options.loop).toBe(true);
+  expect(webslides.options.minWheelDelta).toBe(40);
+  expect(webslides.options.navigateOnScroll).toBe(true);
+  expect(webslides.options.scrollWait).toBe(450);
+  expect(webslides.options.slideOffset).toBe(50);
+});
+
+test('Should be able to define vertical WS', () => {
+  ws.classList.add('vertical');
+  webslides = new WebSlides();
+
+  expect(webslides.isVertical).toBe(true);
+});
+
+test('Should remove all elements that are not sections', () => {
+  expect(document.getElementById('other')).toBeNull();
+});
+
+test('Ready', () => {
+  // Already initialised
+  expect(document.documentElement.classList.contains('ws-ready')).toBe(true);
+  document.documentElement.classList.remove('ws-ready');
+  const listener = jest.fn();
+
+  ws.addEventListener('ws:init', listener);
+  webslides.initialised = false;
+  webslides.onInit_();
+  expect(listener).toHaveBeenCalled();
+  expect(document.documentElement.classList.contains('ws-ready')).toBe(true);
+  expect(webslides.initialised).toBe(true);
+});
+
+test('Should be possible to init with a different slide', () => {
+  location.hash = '#slide=4';
+  webslides = new WebSlides();
+  expect(webslides.currentSlideI_).toBe(3);
+});
+
+describe('Go to slide', () => {
+  beforeEach(() => {
+    jest.spyOn(webslides, 'scrollTransitionToSlide_');
+    jest.spyOn(webslides, 'transitionToSlide_');
   });
-  expect(webslides.plugins.autoslide).not.toBe(null);
-  expect(webslides.plugins.clickNav).not.toBe(null);
-  expect(webslides.plugins.grid).not.toBe(null);
-  expect(webslides.plugins.hash).not.toBe(null);
-  expect(webslides.plugins.keyboard).not.toBe(null);
-  expect(webslides.plugins.nav).not.toBe(null);
-  expect(webslides.plugins.scroll).not.toBe(null);
-  expect(webslides.plugins.touch).not.toBe(null);
-  expect(webslides.plugins.video).not.toBe(null);
-  expect(webslides.plugins.youtube).not.toBe(null);
-  expect(webslides.plugins.zoom).not.toBe(null);
 
-  expect(change.mock.calls.length).toBe(0);
-  webslides.goToSlide(2, true);
-  // Wait until next execution
-  jest.runTimersToTime(501);
+  test('Shouldn\'t allow to go to invalid indexes', () => {
+    webslides.goToSlide(-4);
+    webslides.goToSlide(null);
+    webslides.goToSlide(99);
 
-  expect(change.mock.calls.length).toBe(1);
-  expect(document.querySelector('#webslides .slide').getAttribute('id'))
-    .toBe(webslides.slides[1].el.getAttribute('id'));
-  webslides.goPrev();
-  // Wait until next execution
-  jest.runTimersToTime(501);
-  expect(change.mock.calls.length).toBe(2);
-  expect(document.querySelector('#webslides .slide').getAttribute('id'))
-    .toBe(webslides.slides[1].el.getAttribute('id'));
-  webslides.goNext();
-  // Wait until next execution
-  jest.runTimersToTime(501);
-  expect(change.mock.calls.length).toBe(3);
-  expect(document.querySelector('#webslides .slide').getAttribute('id'))
-    .toBe(webslides.slides[2].el.getAttribute('id'));
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).not.toHaveBeenCalled();
+  });
 
-  const zoom = document.getElementById('webslides-zoomed');
-  expect(zoom).not.toBe(null);
-  expect(webslides.el.style.display).toBe('');
-  expect(zoom.style.display).toBe('none');
-  webslides.toggleZoom();
+  test('Shouldn\'t allow to move if already moving', () => {
+    webslides.isMoving = true;
+    webslides.goToSlide(2);
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).not.toHaveBeenCalled();
+  });
+
+  test('Shouldn\'t allow to move if going to same slide', () => {
+    webslides.goToSlide(0);
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).not.toHaveBeenCalled();
+  });
+
+  test('Shouldn\'t use Scroll if first slide', () => {
+    webslides.isVertical = true;
+    webslides.currentSlide_ = null;
+
+    webslides.goToSlide(1);
+
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).toHaveBeenCalled();
+  });
+
+  test('Shouldn\'t use Scroll if not vertical', () => {
+    webslides.isVertical = false;
+    webslides.goToSlide(1);
+
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).toHaveBeenCalled();
+  });
+
+  test('Shouldn\'t use Scroll if no touch or not enabled', () => {
+    webslides.plugins.touch = null;
+    webslides.goToSlide(1);
+
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).toHaveBeenCalled();
+    webslides.transitionToSlide_.mockClear();
+
+    webslides.plugins.touch = {
+      isEnabled: false
+    };
+
+    webslides.goToSlide(2);
+
+    expect(webslides.scrollTransitionToSlide_).not.toHaveBeenCalled();
+    expect(webslides.transitionToSlide_).toHaveBeenCalled();
+  });
+
+  test('Forward should be true if moving ahead or forced', () => {
+    const getIsMovingForward = () =>
+        webslides.transitionToSlide_.mock.calls[0][0];
+
+    webslides.goToSlide(2);
+    expect(getIsMovingForward()).toBe(true);
+    webslides.transitionToSlide_.mockClear();
+
+    // Going back
+    webslides.goToSlide(1);
+    expect(getIsMovingForward()).toBe(false);
+    webslides.transitionToSlide_.mockClear();
+
+    // Going forward but forced
+    webslides.goToSlide(3, false);
+    expect(getIsMovingForward()).toBe(false);
+    webslides.transitionToSlide_.mockClear();
+  });
+
+  test('Should pass correct arguments to transition to slide', () => {
+    webslides.goToSlide(2);
+    const args = webslides.transitionToSlide_.mock.calls[0];
+
+    expect(args[1]).toBeInstanceOf(Slide);
+    expect(args[1]).toBe(webslides.slides[2]);
+    expect(args[2]).toBe(webslides.onSlideChange_);
+  });
+
+  test('Should pass correct arguments to scroll to slide', () => {
+    webslides.isVertical = true;
+    webslides.goToSlide(2);
+    const args = webslides.scrollTransitionToSlide_.mock.calls[0];
+
+    expect(args[1]).toBeInstanceOf(Slide);
+    expect(args[1]).toBe(webslides.slides[2]);
+    expect(args[2]).toBe(webslides.onSlideChange_);
+  });
+
+  test('After move', () => {
+    webslides.isVertical = true;
+    const mock = jest.fn();
+    const currentSlide = webslides.currentSlide_;
+    webslides.el.addEventListener('ws:slide-change', mock);
+
+    webslides.goToSlide(1);
+    expect(webslides.isMoving).toBe(true);
+    jest.runAllTimers();
+    expect(webslides.isMoving).toBe(false);
+    expect(webslides.currentSlide_).not.toBe(currentSlide);
+    expect(webslides.currentSlide_).toBe(webslides.slides[1]);
+    expect(webslides.currentSlideI_).toBe(1);
+    expect(currentSlide.el.style.display).toBe('none');
+
+    const mockEvent = mock.mock.calls[0][0].detail;
+    expect(mockEvent.slides).toBe(webslides.maxSlide_);
+    expect(mockEvent.currentSlide0).toBe(1);
+    expect(mockEvent.currentSlide).toBe(2);
+  });
+});
+
+describe('Go next/prev', () => {
+  beforeEach(() => {
+    jest.spyOn(webslides, 'goToSlide');
+  });
+
+  test('Go next should go to the next slide', () => {
+    webslides.goNext();
+    expect(webslides.goToSlide).toHaveBeenCalledWith(1, true);
+  });
+
+  test('Go prev should go to the previous slide', () => {
+    webslides.currentSlideI_ = 2;
+    webslides.goPrev();
+    expect(webslides.goToSlide).toHaveBeenCalledWith(1, false);
+  });
+
+  test('Should not be possible to move if loop is disabled and on edge', () => {
+    webslides.options.loop = false;
+    webslides.goPrev();
+    expect(webslides.goToSlide).not.toHaveBeenCalled();
+    webslides.currentSlideI_ = webslides.maxSlide_;
+    webslides.goNext();
+    expect(webslides.goToSlide).not.toHaveBeenCalled();
+  });
+
+  test('It should loop correctly', () => {
+    webslides.currentSlideI_ = webslides.maxSlide_ - 1;
+    webslides.goNext();
+    expect(webslides.goToSlide).toHaveBeenCalledWith(0, true);
+
+    webslides.goPrev();
+    expect(webslides.goToSlide).toHaveBeenCalledWith(19, false);
+  });
+});
+
+describe('Scroll to', () => {
+  test('Overflow should be removed and resetted', () => {
+    webslides.scrollTransitionToSlide_(true, webslides.slides[1], () => {});
+    expect(webslides.el.style.overflow).toBe('hidden');
+    jest.runAllTimers();
+    expect(webslides.el.style.overflow).not.toBe('hidden');
+  });
+
+  test('Should move slide if not moving forward', () => {
+    const getHTML = () => webslides.el.innerHTML;
+
+    expect(getHTML().indexOf('section-1"'))
+      .toBeLessThan(getHTML().indexOf('section-20"'));
+
+    webslides.scrollTransitionToSlide_(false, webslides.slides[19], () => {});
+
+    expect(getHTML().indexOf('section-20"'))
+      .toBeLessThan(getHTML().indexOf('section-1"'));
+  });
+
+  test('Should not move slide if moving forward', () => {
+    const getHTML = () => webslides.el.innerHTML;
+
+    expect(getHTML().indexOf('section-1"'))
+      .toBeLessThan(getHTML().indexOf('section-2"'));
+
+    webslides.scrollTransitionToSlide_(true, webslides.slides[1], () => {});
+
+    expect(getHTML().indexOf('section-1"'))
+      .toBeLessThan(getHTML().indexOf('section-2"'));
+  });
+
+  test('Should call the callback once finished with the next slide', () => {
+    const cb = jest.fn();
+
+    webslides.scrollTransitionToSlide_(true, webslides.slides[1], cb);
+    expect(cb).not.toHaveBeenCalled();
+    jest.runAllTimers();
+    expect(cb).toHaveBeenCalledWith(webslides.slides[1]);
+  });
+});
+
+describe('Transition to', () => {
+  test('Should move slide if not moving forward', () => {
+    const getHTML = () => webslides.el.innerHTML;
+
+    expect(getHTML().indexOf('section-1"'))
+      .toBeLessThan(getHTML().indexOf('section-20"'));
+
+    webslides.transitionToSlide_(false, webslides.slides[19], () => {});
+
+    expect(getHTML().indexOf('section-20"'))
+      .toBeLessThan(getHTML().indexOf('section-1"'));
+  });
+
+  test('Should move current slide to last if moving forward', () => {
+    const getHTML = () => webslides.el.innerHTML;
+
+    expect(getHTML().indexOf('section-1'))
+      .toBeLessThan(getHTML().indexOf('section-2'));
+
+    webslides.transitionToSlide_(true, webslides.slides[1], () => {});
+
+    expect(getHTML().indexOf('section-1"'))
+      .toBeGreaterThan(getHTML().indexOf('section-20"'));
+  });
+
+  test('Should slideInRight if touch and moving forward', () => {
+    const callback = jest.fn();
+    const nextSlideEl = webslides.slides[19].el;
+    webslides.initialised = true;
+    webslides.plugins.touch = {
+      isEnabled: true
+    };
+
+    webslides.transitionToSlide_(true, webslides.slides[19], callback);
+    expect(nextSlideEl.classList.contains('slideInRight'))
+      .toBe(true);
+    expect(callback).not.toBeCalled();
+    DOM.fireEvent(nextSlideEl, 'animationend');
+    expect(callback).toHaveBeenCalledWith(webslides.slides[19]);
+    expect(nextSlideEl.classList.contains('slideInRight'))
+      .toBe(false);
+  });
+
+  test('Should slideInLeft if touch and not moving forward', () => {
+    const callback = jest.fn();
+    const nextSlideEl = webslides.slides[1].el;
+    webslides.initialised = true;
+    webslides.plugins.touch = {
+      isEnabled: true
+    };
+
+    webslides.transitionToSlide_(false, webslides.slides[1], callback);
+    expect(nextSlideEl.classList.contains('slideInLeft'))
+      .toBe(true);
+    expect(callback).not.toBeCalled();
+    DOM.fireEvent(nextSlideEl, 'animationend');
+    expect(callback).toHaveBeenCalledWith(webslides.slides[1]);
+    expect(nextSlideEl.classList.contains('slideInLeft'))
+      .toBe(false);
+  });
+});
+
+test('Enable/Disable', () => {
+  expect(webslides.isDisabled()).toBe(false);
+  expect(webslides.el.classList.contains('disabled')).toBe(false);
   webslides.disable();
   expect(webslides.el.classList.contains('disabled')).toBe(true);
   expect(webslides.isDisabled()).toBe(true);
+
   webslides.enable();
   expect(webslides.isDisabled()).toBe(false);
 
+  expect(webslides.el.classList.contains('disabled')).toBe(false);
+});
 
+test('Fullscreen', () => {
+  // Mocking FullScreen API
   document.fullscreen = false;
   document.documentElement.requestFullscreen = jest.fn();
   document.exitFullScreen = jest.fn();
@@ -83,3 +383,26 @@ test('WebSlides utility', () => {
   webslides.fullscreen();
   expect(document.exitFullScreen.mock.calls.length).toBe(1);
 });
+
+test('Zoom', () => {
+  webslides.plugins.zoom = {
+    toggleZoom: jest.fn()
+  };
+
+  expect(webslides.plugins.zoom.toggleZoom).not.toHaveBeenCalled();
+  webslides.toggleZoom();
+  expect(webslides.plugins.zoom.toggleZoom).toHaveBeenCalled();
+});
+
+test('Plugin register', () => {
+  const cto = jest.fn();
+  const Mock = function() {
+    cto();
+  };
+
+  WebSlides.registerPlugin('mock', Mock);
+  webslides = new WebSlides();
+
+  expect(cto).toHaveBeenCalled();
+  expect(webslides.plugins.mock).toBeDefined();
+});