diff --git a/test/utils/hash.test.js b/test/utils/hash.test.js
index 31945be..9479b87 100644
--- a/test/utils/hash.test.js
+++ b/test/utils/hash.test.js
@@ -1,12 +1,10 @@
 import DOM from '../../src/js/utils/dom';
 import Hash from '../../src/js/plugins/hash';
 
-beforeAll(() => {
+describe('Hash utility', () => {
   document.body.innerHTML =
       `<div id="webslides" data-test="test"><p>Text</p></div>`;
-});
 
-test('Hash plugin', () => {
   document.location.hash = '#slide=1';
   const goto = jest.fn();
   const ws = document.getElementById('webslides');
@@ -20,19 +18,46 @@ test('Hash plugin', () => {
     el: ws
   };
 
-  expect(goto).not.toBeCalled();
+  test('Make sure it has not changed the slide', () => {
+    expect(goto).not.toBeCalled();
+  });
 
   new Hash(webslides);
 
-  expect(Hash.getSlideNumber()).toBe(0);
-  DOM.fireEvent(ws, 'ws:slide-change', {
-    slides: 3,
-    currentSlide0: 1,
-    currentSlide: 2
-  });
-  expect(Hash.getSlideNumber()).toBe(1);
-  expect(document.location.hash).toBe('#slide=2');
+  test('Move to slide 1', () => {
+    expect(Hash.getSlideNumber()).toBe(0);
+    DOM.fireEvent(ws, 'ws:slide-change', {
+      slides: 3,
+      currentSlide0: 1,
+      currentSlide: 2
+    });
+    expect(Hash.getSlideNumber()).toBe(1);
+    expect(document.location.hash).toBe('#slide=2');
 
-  DOM.fireEvent(window, 'hashchange');
-  expect(goto.mock.calls.length).toBe(1);
+    DOM.fireEvent(window, 'hashchange');
+    expect(goto.mock.calls.length).toBe(1);
+  });
+
+  test('Forces slide change', () => {
+    Hash.setSlideNumber(5);
+    const state = history.state;
+    expect(state.slideI).toBe(4);
+  });
+
+  test('Wrong hash', () => {
+    document.location.hash = 'slide=NaN';
+    DOM.fireEvent(window, 'hashchange');
+    // It shouldn't be call.
+    expect(goto.mock.calls.length).toBe(1);
+    expect(Hash.getSlideNumber()).toBe(null);
+  });
+
+  test('Repeat slide change', () => {
+    Hash.setSlideNumber(5);
+    let state = history.state;
+    expect(state.slideI).toBe(4);
+    Hash.setSlideNumber(5);
+    state = history.state;
+    expect(state.slideI).toBe(4);
+  });
 });