Use ava for tests

package.json

@@ -12,7 +12,7 @@
     "index.js"
   ],
   "scripts": {
-    "test": "bash test.sh"
+    "test": "ava"
   },
   "keywords": [
     "json",
@@ -25,5 +25,8 @@
     "cardinal": "^1.0.0",
     "get-stdin": "^5.0.1",
     "meow": "^4.0.0"
+  },
+  "devDependencies": {
+    "ava": "^0.24.0"
   }
 }

test.js

@@ -0,0 +1,28 @@
+'use strict'
+const test = require('ava')
+const {execSync} = require('child_process')
+
+function fx(json, code = '') {
+  const output = execSync(`echo '${JSON.stringify(json)}' | node index.js ${code}`).toString('utf8')
+  return JSON.parse(output)
+}
+
+test('pass', t => {
+  t.deepEqual(fx([{"greeting": "hello world"}]), [{"greeting": "hello world"}])
+})
+
+test('anon func', t => {
+  t.deepEqual(fx({"key": "value"}, "'x => x.key'"), 'value')
+})
+
+test('this bind', t => {
+  t.deepEqual(fx([1, 2, 3, 4, 5], "'this.map(x => x * this.length)'"), [5, 10, 15, 20, 25])
+})
+
+test('generator', t => {
+  t.deepEqual(fx([1, 2, 3, 4, 5], "'for (let i of this) if (i % 2 == 0) yield i'"), [2, 4])
+})
+
+test('chain', t => {
+  t.deepEqual(fx({"items": ["foo", "bar"]}, "'this.items' 'yield* this' 'x => x[1]'"), 'bar')
+})

test.sh

@@ -1,9 +0,0 @@
-#!/usr/bin/env bash
-set -euxo pipefail
-readonly fx='node index.js'
-
-echo '[{"greeting": "hello world"}]' | $fx
-echo '{"key": "value"}' | $fx "x => x.key"
-echo '[1, 2, 3, 4, 5]' | $fx "this.map(x => x * this.length)"
-echo '[1, 2, 3, 4, 5]' | $fx "for (let i of this) if (i % 2 == 0) yield i"
-echo '{"items": ["foo", "bar"]}' | $fx "this.items" "yield* this; yield 'baz'"