Add test

tests/ffmpeg.test.js

@@ -0,0 +1,22 @@
+const { createWorker } = FFmpeg;
+const worker = createWorker(OPTIONS);
+
+before(async function cb() {
+  this.timeout(0);
+  await worker.load();
+});
+
+describe('transcode()', () => {
+  describe('should transcode different format', () => {
+    ['flame.avi'].forEach((name) => (
+      it(`transcode ${name}`, async () => {
+        await worker.write(name, `${BASE_URL}/${name}`);
+        await worker.transcode(name, 'output.mp4');
+        await worker.remove(name);
+        const { data } = await worker.read('output.mp4');
+        await worker.remove('output.mp4');
+        expect(data.length).to.be(FLAME_MP4_LENGTH);
+      }).timeout(TIMEOUT)
+    ));
+  });
+});