add integration testing script

integration.js

@@ -0,0 +1,43 @@
+const assert = require('assert');
+const fetch = require('node-fetch');
+
+const infoHash = '(m.%5bO%83i%85S(3j%c1%26%3a%e0*z%60%d5';
+(async () => {
+  if (!process.env.ENDPOINT) {
+    throw new Error('Endpoint must be defined.');
+  }
+  console.log(`testing ${process.env.ENDPOINT} with infoHash '${infoHash}'`);
+
+  const res = await fetch(
+    `${process.env.ENDPOINT}/fetch?info_hash=${infoHash}&json=1`,
+  );
+  assert.deepEqual(res.status, 200, 'expected response to be ok');
+
+  const data = await res.json();
+  assert.deepEqual(
+    typeof data,
+    'object',
+    'expected response to be an array (is not an object)',
+  );
+  assert.ok(
+    data instanceof Array,
+    'expected response to be an array (is not an object)',
+  );
+  assert.ok(data.length > 0, 'expected popular torrent to have peers');
+  data.forEach((peer) => {
+    assert.deepEqual(
+      typeof peer,
+      'string',
+      'expected every response entry to be a string',
+    );
+    assert.match(
+      peer,
+      /[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\:[0-9]{1,5}/,
+      'expected every response entry to resemble ip:port',
+    );
+  });
+})().catch((e) => {
+  console.log(e);
+  process.exit(1);
+});
+