Added unit tests

app/assets/javascripts/blob/balsamiq/balsamiq_viewer.js

 /* global Flash */
 
-import Spinner from '../../spinner';
 import sqljs from 'sql.js';
+import Spinner from '../../spinner';
 
 class BalsamiqViewer {
   constructor(viewer) {
@@ -32,7 +32,7 @@ class BalsamiqViewer {
     this.initDatabase(loadEvent.target.response);
 
     const previews = this.getPreviews();
-    const renderedPreviews = previews.map(preview => this.renderPreview(preview, container));
+    const renderedPreviews = previews.map(preview => this.renderPreview(preview));
 
     container.innerHTML = renderedPreviews.join('');
     container.classList.add('list-inline', 'previews');
@@ -68,7 +68,7 @@ class BalsamiqViewer {
     const name = JSON.parse(title[0].values[0][2]).name;
     const image = preview.image;
 
-    template = template.replace(/{{name}}/, name).replace(/{{image}}/, image);
+    template = template.replace(/{{name}}/g, name).replace(/{{image}}/g, image);
 
     return template;
   }

spec/javascripts/spinner_spec.js

+import Spinner from '~/spinner';
+import ClassSpecHelper from './helpers/class_spec_helper';
+
+describe('Spinner', () => {
+  let renderable;
+  let container;
+  let spinner;
+
+  describe('class constructor', () => {
+    beforeEach(() => {
+      renderable = {};
+      container = {};
+
+      spyOn(Spinner, 'createContainer').and.returnValue(container);
+
+      spinner = new Spinner(renderable);
+    });
+
+    it('should set .renderable', () => {
+      expect(spinner.renderable).toBe(renderable);
+    });
+
+    it('should call Spinner.createContainer', () => {
+      expect(Spinner.createContainer).toHaveBeenCalled();
+    });
+
+    it('should set .container', () => {
+      expect(spinner.container).toBe(container);
+    });
+  });
+
+  describe('start', () => {
+    beforeEach(() => {
+      renderable = jasmine.createSpyObj('renderable', ['prepend']);
+      container = {};
+
+      spinner = {
+        renderable,
+        container,
+      };
+
+      Spinner.prototype.start.call(spinner);
+    });
+
+    it('should call .prepend', () => {
+      expect(renderable.prepend).toHaveBeenCalledWith(container);
+    });
+  });
+
+  describe('stop', () => {
+    beforeEach(() => {
+      container = jasmine.createSpyObj('container', ['remove']);
+
+      spinner = {
+        container,
+      };
+
+      Spinner.prototype.stop.call(spinner);
+    });
+
+    it('should call .remove', () => {
+      expect(container.remove).toHaveBeenCalled();
+    });
+  });
+
+  describe('createContainer', () => {
+    let createContainer;
+
+    beforeEach(() => {
+      container = {
+        classList: jasmine.createSpyObj('classList', ['add']),
+      };
+
+      spyOn(document, 'createElement').and.returnValue(container);
+
+      createContainer = Spinner.createContainer();
+    });
+
+    ClassSpecHelper.itShouldBeAStaticMethod(Spinner, 'createContainer');
+
+    it('should call document.createElement', () => {
+      expect(document.createElement).toHaveBeenCalledWith('div');
+    });
+
+    it('should call classList.add', () => {
+      expect(container.classList.add).toHaveBeenCalledWith('loading');
+    });
+
+    it('should return the container element', () => {
+      expect(createContainer).toBe(container);
+    });
+
+    it('should set the container .innerHTML to Spinner.TEMPLATE', () => {
+      expect(container.innerHTML).toBe(Spinner.TEMPLATE);
+    });
+  });
+});