Bump AVA version and improve tests

package.json

@@ -24,7 +24,7 @@
     "node": ">=4"
   },
   "scripts": {
-    "test": "node test/test.js"
+    "test": "ava"
   },
   "files": [
     "index.js"
@@ -46,8 +46,8 @@
     "jpeg-recompress-bin": "^3.0.1"
   },
   "devDependencies": {
-    "ava": "^0.0.4",
-    "buffer-equal": "^0.0.1",
-    "is-progressive": "^1.0.1"
+    "ava": "*",
+    "is-progressive": "^1.0.1",
+    "pify": "^2.3.0"
   }
 }

test.js

@@ -0,0 +1,37 @@
+import fs from 'fs';
+import path from 'path';
+import isJpg from 'is-jpg';
+import isProgressive from 'is-progressive';
+import pify from 'pify';
+import test from 'ava';
+import m from './';
+
+const fsP = pify(fs);
+
+test('optimize a JPG', async t => {
+	const buf = await fsP.readFile(path.join(__dirname, 'fixture.jpg'));
+	const data = await m()(buf);
+
+	t.true(data.length < buf.length);
+	t.true(isJpg(data));
+	t.true(isProgressive.buffer(data));
+});
+
+test('support jpeg-recompress options', async t => {
+	const buf = await fsP.readFile(path.join(__dirname, 'fixture.jpg'));
+	const data = await m({progressive: false})(buf);
+
+	t.false(isProgressive.buffer(data));
+});
+
+test('skip optimizing a non-JPG file', async t => {
+	const buf = await fsP.readFile(__filename);
+	const data = await m()(buf);
+
+	t.deepEqual(data, buf);
+});
+
+test('throw error when a JPG is corrupt', async t => {
+	const buf = await fsP.readFile(path.join(__dirname, 'fixture-corrupt.jpg'));
+	t.throws(m()(buf), /Corrupt JPEG data/);
+});