Load a preview of Sketch 43 files

Sketch 43 files are technically a zip file, so the JavaScript opens the
zip file & locates a preview.png which is just a quick preview of the
last sketch page edited. After that is loaded it simply places the image
into the DOM

1 files changed, 118 insertions, 0 deletions

diff --git a/spec/javascripts/blob/sketch/index_spec.js b/spec/javascripts/blob/sketch/index_spec.js
new file mode 100644
index 00000000000..0e4431548c4
--- /dev/null
+++ b/spec/javascripts/blob/sketch/index_spec.js
@@ -0,0 +1,118 @@
+/* eslint-disable no-new */
+import JSZip from 'jszip';
+import SketchLoader from '~/blob/sketch';
+
+describe('Sketch viewer', () => {
+  const generateZipFileArrayBuffer = (zipFile, resolve, done) => {
+    zipFile
+      .generateAsync({ type: 'arrayBuffer' })
+      .then((content) => {
+        resolve(content);
+
+        setTimeout(() => {
+          done();
+        }, 100);
+      });
+  };
+
+  preloadFixtures('static/sketch_viewer.html.raw');
+
+  beforeEach(() => {
+    loadFixtures('static/sketch_viewer.html.raw');
+  });
+
+  describe('with error message', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve, reject) => {
+        reject();
+
+        setTimeout(() => {
+          done();
+        });
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('renders error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).not.toBeNull();
+
+      expect(
+        document.querySelector('#js-sketch-viewer p').textContent.trim(),
+      ).toContain('Cannot show preview.');
+    });
+
+    it('removes render the loading icon', () => {
+      expect(
+        document.querySelector('.js-loading-icon'),
+      ).toBeNull();
+    });
+  });
+
+  describe('success', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve) => {
+        const zipFile = new JSZip();
+        zipFile.folder('previews')
+          .file('preview.png', 'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAMAAAAoyzS7AAAAA1BMVEUAAACnej3aAAAAAXRSTlMAQObYZgAAAA1JREFUeNoBAgD9/wAAAAIAAVMrnDAAAAAASUVORK5CYII=', {
+            base64: true,
+          });
+
+        generateZipFileArrayBuffer(zipFile, resolve, done);
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('does not render error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).toBeNull();
+    });
+
+    it('removes render the loading icon', () => {
+      expect(
+        document.querySelector('.js-loading-icon'),
+      ).toBeNull();
+    });
+
+    it('renders preview img', () => {
+      const img = document.querySelector('#js-sketch-viewer img');
+
+      expect(img).not.toBeNull();
+      expect(img.classList.contains('img-responsive')).toBeTruthy();
+    });
+
+    it('renders link to image', () => {
+      const img = document.querySelector('#js-sketch-viewer img');
+      const link = document.querySelector('#js-sketch-viewer a');
+
+      expect(link.href).toBe(img.src);
+      expect(link.target).toBe('_blank');
+    });
+  });
+
+  describe('incorrect file', () => {
+    beforeEach((done) => {
+      spyOn(SketchLoader.prototype, 'getZipFile').and.callFake(() => new Promise((resolve) => {
+        const zipFile = new JSZip();
+
+        generateZipFileArrayBuffer(zipFile, resolve, done);
+      }));
+
+      new SketchLoader(document.getElementById('js-sketch-viewer'));
+    });
+
+    it('renders error message', () => {
+      expect(
+        document.querySelector('#js-sketch-viewer p'),
+      ).not.toBeNull();
+
+      expect(
+        document.querySelector('#js-sketch-viewer p').textContent.trim(),
+      ).toContain('Cannot show preview.');
+    });
+  });
+});