diff --git a/test/auth.js b/test/auth.js
index 676b136..2ea9941 100644
--- a/test/auth.js
+++ b/test/auth.js
@@ -1,19 +1,19 @@
-var concat = require('simple-concat')
-var get = require('../')
-var http = require('http')
-var test = require('tape')
+const concat = require('simple-concat')
+const get = require('../')
+const http = require('http')
+const test = require('tape')
 
 test('basic auth', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.headers.authorization, 'Basic Zm9vOmJhcg==')
     res.statusCode = 200
     res.end('response')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://foo:bar@localhost:' + port, function (err, res) {
       t.error(err)
       t.equal(res.statusCode, 200)
diff --git a/test/basic.js b/test/basic.js
index 07846ee..3188482 100644
--- a/test/basic.js
+++ b/test/basic.js
@@ -1,20 +1,20 @@
-var concat = require('simple-concat')
-var get = require('../')
-var http = require('http')
-var selfSignedHttps = require('self-signed-https')
-var test = require('tape')
+const concat = require('simple-concat')
+const get = require('../')
+const http = require('http')
+const selfSignedHttps = require('self-signed-https')
+const test = require('tape')
 
 test('simple get', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/path')
     res.statusCode = 200
     res.end('response')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://localhost:' + port + '/path', function (err, res) {
       t.error(err)
       t.equal(res.statusCode, 200)
@@ -30,14 +30,14 @@ test('simple get', function (t) {
 test('https', function (t) {
   t.plan(5)
 
-  var server = selfSignedHttps(function (req, res) {
+  const server = selfSignedHttps(function (req, res) {
     t.equal(req.url, '/path')
     res.statusCode = 200
     res.end('response')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get({
       url: 'https://localhost:' + port + '/path',
       rejectUnauthorized: false
@@ -56,7 +56,7 @@ test('https', function (t) {
 test('simple get json', function (t) {
   t.plan(6)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/path')
     t.equal(req.headers.accept, 'application/json')
     res.statusCode = 200
@@ -64,8 +64,8 @@ test('simple get json', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port + '/path',
       json: true
     }
@@ -84,7 +84,7 @@ test('simple get json', function (t) {
 test('HEAD request', function (t) {
   t.plan(3)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'HEAD')
     // Taken from real-world response from HEAD request to GitHub.com
     res.setHeader('content-type', 'text/html; charset=utf-8')
@@ -95,8 +95,8 @@ test('HEAD request', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       method: 'HEAD',
       url: 'http://localhost:' + port
     }
@@ -111,7 +111,7 @@ test('HEAD request', function (t) {
 test('timeout option', function (t) {
   t.plan(2)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/path')
     setTimeout(function () {
       // response should not be sent - should timeout before it's sent
@@ -120,7 +120,7 @@ test('timeout option', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get({
       url: 'http://localhost:' + port + '/path',
       timeout: 1000
@@ -134,9 +134,9 @@ test('timeout option', function (t) {
 test('rewrite POST redirects to GET', function (t) {
   t.plan(8)
 
-  var redirected = false
+  let redirected = false
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     if (redirected) {
       t.equal(req.url, '/getthis')
       t.equal(req.method, 'GET')
@@ -153,8 +153,8 @@ test('rewrite POST redirects to GET', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       method: 'POST',
       body: '123',
       url: 'http://localhost:' + port
diff --git a/test/concat.js b/test/concat.js
index 4a97065..2bc22c9 100644
--- a/test/concat.js
+++ b/test/concat.js
@@ -1,19 +1,19 @@
-var get = require('../')
-var http = require('http')
-var str = require('string-to-stream')
-var test = require('tape')
+const get = require('../')
+const http = require('http')
+const str = require('string-to-stream')
+const test = require('tape')
 
 test('get.concat (post, stream body, and json option)', function (t) {
   t.plan(4)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     req.pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port,
       body: str('{"a": "b"}'),
       method: 'POST',
@@ -31,13 +31,13 @@ test('get.concat (post, stream body, and json option)', function (t) {
 
 test('get.concat', function (t) {
   t.plan(4)
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     res.end('blah blah blah')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get.concat('http://localhost:' + port, function (err, res, data) {
       t.error(err)
       t.equal(res.statusCode, 200)
@@ -50,14 +50,14 @@ test('get.concat', function (t) {
 
 test('get.concat json', function (t) {
   t.plan(3)
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     res.end('{"message":"response"}')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port + '/path',
       json: true
     }
@@ -72,14 +72,14 @@ test('get.concat json', function (t) {
 
 test('get.concat json error', function (t) {
   t.plan(1)
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 500
     res.end('not json')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port + '/path',
       json: true
     }
diff --git a/test/headers.js b/test/headers.js
index a22c8e8..ac51f81 100644
--- a/test/headers.js
+++ b/test/headers.js
@@ -1,21 +1,21 @@
-var concat = require('simple-concat')
-var get = require('../')
-var http = require('http')
-var str = require('string-to-stream')
-var test = require('tape')
-var zlib = require('zlib')
+const concat = require('simple-concat')
+const get = require('../')
+const http = require('http')
+const str = require('string-to-stream')
+const test = require('tape')
+const zlib = require('zlib')
 
 test('custom headers', function (t) {
   t.plan(2)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.headers['custom-header'], 'custom-value')
     res.statusCode = 200
     res.end('response')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get({
       url: 'http://localhost:' + port,
       headers: {
@@ -32,14 +32,14 @@ test('custom headers', function (t) {
 test('gzip response', function (t) {
   t.plan(4)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     res.setHeader('content-encoding', 'gzip')
     str('response').pipe(zlib.createGzip()).pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://localhost:' + port, function (err, res) {
       t.error(err)
       t.equal(res.statusCode, 200) // statusCode still works on gunzip stream
@@ -55,14 +55,14 @@ test('gzip response', function (t) {
 test('deflate response', function (t) {
   t.plan(4)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     res.setHeader('content-encoding', 'deflate')
     str('response').pipe(zlib.createDeflate()).pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://localhost:' + port, function (err, res) {
       t.error(err)
       t.equal(res.statusCode, 200) // statusCode still works on inflate stream
diff --git a/test/post.js b/test/post.js
index a02c09e..b0ae806 100644
--- a/test/post.js
+++ b/test/post.js
@@ -1,22 +1,22 @@
-var concat = require('simple-concat')
-var get = require('../')
-var http = require('http')
-var querystring = require('querystring')
-var str = require('string-to-stream')
-var test = require('tape')
+const concat = require('simple-concat')
+const get = require('../')
+const http = require('http')
+const querystring = require('querystring')
+const str = require('string-to-stream')
+const test = require('tape')
 
 test('post (text body)', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     res.statusCode = 200
     req.pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port,
       body: 'this is the body'
     }
@@ -35,15 +35,15 @@ test('post (text body)', function (t) {
 test('post (utf-8 text body)', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     res.statusCode = 200
     req.pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port,
       body: 'jedan dva tri četiri'
     }
@@ -62,15 +62,15 @@ test('post (utf-8 text body)', function (t) {
 test('post (buffer body)', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     res.statusCode = 200
     req.pipe(res)
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port,
       body: Buffer.from('this is the body')
     }
@@ -89,7 +89,7 @@ test('post (buffer body)', function (t) {
 test('post (stream body)', function (t) {
   t.plan(6)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     res.statusCode = 200
     t.notOk(req.headers['content-length'])
@@ -97,8 +97,8 @@ test('post (stream body)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       url: 'http://localhost:' + port,
       body: str('this is the body')
     }
@@ -117,7 +117,7 @@ test('post (stream body)', function (t) {
 test('post (json body)', function (t) {
   t.plan(5)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     t.equal(req.headers['content-type'], 'application/json')
     res.statusCode = 200
@@ -125,8 +125,8 @@ test('post (json body)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       method: 'POST',
       url: 'http://localhost:' + port,
       body: {
@@ -146,10 +146,10 @@ test('post (json body)', function (t) {
 test('post (form, object)', function (t) {
   t.plan(5)
 
-  var formData = Object.create(null)
+  const formData = Object.create(null)
   formData.foo = 'bar'
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     t.equal(req.headers['content-type'], 'application/x-www-form-urlencoded')
     res.statusCode = 200
@@ -157,8 +157,8 @@ test('post (form, object)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       method: 'POST',
       url: 'http://localhost:' + port,
       form: formData
@@ -175,9 +175,9 @@ test('post (form, object)', function (t) {
 test('post (form, querystring)', function (t) {
   t.plan(5)
 
-  var formData = 'foo=bar'
+  const formData = 'foo=bar'
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.method, 'POST')
     t.equal(req.headers['content-type'], 'application/x-www-form-urlencoded')
     res.statusCode = 200
@@ -185,8 +185,8 @@ test('post (form, querystring)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var opts = {
+    const port = server.address().port
+    const opts = {
       method: 'POST',
       url: 'http://localhost:' + port,
       form: formData
diff --git a/test/redirect.js b/test/redirect.js
index 26131a6..2f06edd 100644
--- a/test/redirect.js
+++ b/test/redirect.js
@@ -1,14 +1,14 @@
-var concat = require('simple-concat')
-var get = require('../')
-var http = require('http')
-var selfSignedHttps = require('self-signed-https')
-var test = require('tape')
+const concat = require('simple-concat')
+const get = require('../')
+const http = require('http')
+const selfSignedHttps = require('self-signed-https')
+const test = require('tape')
 
 test('follow redirects (up to 10)', function (t) {
   t.plan(15)
 
-  var num = 0
-  var server = http.createServer(function (req, res) {
+  let num = 0
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/' + num, 'visited /' + num)
 
     if (num < 10) {
@@ -23,7 +23,7 @@ test('follow redirects (up to 10)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://localhost:' + port + '/0', function (err, res) {
       t.error(err)
       t.equal(res.statusCode, 200)
@@ -39,7 +39,7 @@ test('follow redirects (up to 10)', function (t) {
 test('do not follow redirects', function (t) {
   t.plan(2)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/0', 'visited /0')
 
     res.statusCode = 301
@@ -48,7 +48,7 @@ test('do not follow redirects', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get({
       url: 'http://localhost:' + port + '/0',
       maxRedirects: 0
@@ -62,7 +62,7 @@ test('do not follow redirects', function (t) {
 test('do not follow redirects and do not error', function (t) {
   t.plan(4)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/0', 'visited /0')
 
     res.statusCode = 301
@@ -71,7 +71,7 @@ test('do not follow redirects and do not error', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get({
       url: 'http://localhost:' + port + '/0',
       followRedirects: false
@@ -87,8 +87,8 @@ test('do not follow redirects and do not error', function (t) {
 test('follow redirects (11 is too many)', function (t) {
   t.plan(12)
 
-  var num = 0
-  var server = http.createServer(function (req, res) {
+  let num = 0
+  const server = http.createServer(function (req, res) {
     t.equal(req.url, '/' + num, 'visited /' + num)
 
     if (num < 11) {
@@ -102,7 +102,7 @@ test('follow redirects (11 is too many)', function (t) {
   })
 
   server.listen(0, function () {
-    var port = server.address().port
+    const port = server.address().port
     get('http://localhost:' + port + '/0', function (err) {
       t.ok(err instanceof Error, 'got error')
       server.close()
@@ -113,17 +113,17 @@ test('follow redirects (11 is too many)', function (t) {
 test('redirect https to http', function (t) {
   t.plan(6)
 
-  var httpPort = null
-  var httpsPort = null
+  let httpPort = null
+  let httpsPort = null
 
-  var httpsServer = selfSignedHttps(function (req, res) {
+  const httpsServer = selfSignedHttps(function (req, res) {
     t.equal(req.url, '/path1')
     res.statusCode = 301
     res.setHeader('Location', 'http://localhost:' + httpPort + '/path2')
     res.end()
   })
 
-  var httpServer = http.createServer(function (req, res) {
+  const httpServer = http.createServer(function (req, res) {
     t.equal(req.url, '/path2')
     res.statusCode = 200
     res.end('response')
@@ -153,17 +153,17 @@ test('redirect https to http', function (t) {
 test('redirect http to https', function (t) {
   t.plan(6)
 
-  var httpsPort = null
-  var httpPort = null
+  let httpsPort = null
+  let httpPort = null
 
-  var httpServer = http.createServer(function (req, res) {
+  const httpServer = http.createServer(function (req, res) {
     t.equal(req.url, '/path1')
     res.statusCode = 301
     res.setHeader('Location', 'https://localhost:' + httpsPort + '/path2')
     res.end()
   })
 
-  var httpsServer = selfSignedHttps(function (req, res) {
+  const httpsServer = selfSignedHttps(function (req, res) {
     t.equal(req.url, '/path2')
     res.statusCode = 200
     res.end('response')
@@ -193,10 +193,10 @@ test('redirect http to https', function (t) {
 test('redirect to different host/port', function (t) {
   t.plan(7)
 
-  var port1 = null
-  var port2 = null
+  let port1 = null
+  let port2 = null
 
-  var server1 = http.createServer(function (req, res) {
+  const server1 = http.createServer(function (req, res) {
     t.equal(req.url, '/path1')
     res.statusCode = 301
     // Redirect from localhost:port1 to 127.0.0.1:port2 (different host and port!)
@@ -204,7 +204,7 @@ test('redirect to different host/port', function (t) {
     res.end()
   })
 
-  var server2 = http.createServer(function (req, res) {
+  const server2 = http.createServer(function (req, res) {
     t.equal(req.url, '/path2')
     // Confirm that request was made with new host and port (127.0.0.1:port2)
     t.equal(req.headers.host, `127.0.0.1:${port2}`)
@@ -234,10 +234,10 @@ test('redirect to different host/port', function (t) {
 test('redirect should clear explicitly specified `host` header', function (t) {
   t.plan(8)
 
-  var port1 = null
-  var port2 = null
+  let port1 = null
+  let port2 = null
 
-  var server1 = http.createServer(function (req, res) {
+  const server1 = http.createServer(function (req, res) {
     t.equal(req.url, '/path1')
     t.equal(req.headers.host, `localhost:${port1}`)
     res.statusCode = 301
@@ -246,7 +246,7 @@ test('redirect should clear explicitly specified `host` header', function (t) {
     res.end()
   })
 
-  var server2 = http.createServer(function (req, res) {
+  const server2 = http.createServer(function (req, res) {
     t.equal(req.url, '/path2')
     // Confirm that request was made with new host and port (127.0.0.1:port2), i.e.
     // that the explicitly specified `Host` header was cleared upon redirect.
@@ -282,10 +282,10 @@ test('redirect should clear explicitly specified `host` header', function (t) {
 test('redirect should clear explicitly specified `Host` (note uppercase) header', function (t) {
   t.plan(8)
 
-  var port1 = null
-  var port2 = null
+  let port1 = null
+  let port2 = null
 
-  var server1 = http.createServer(function (req, res) {
+  const server1 = http.createServer(function (req, res) {
     t.equal(req.url, '/path1')
     t.equal(req.headers.host, `localhost:${port1}`)
     res.statusCode = 301
@@ -294,7 +294,7 @@ test('redirect should clear explicitly specified `Host` (note uppercase) header'
     res.end()
   })
 
-  var server2 = http.createServer(function (req, res) {
+  const server2 = http.createServer(function (req, res) {
     t.equal(req.url, '/path2')
     // Confirm that request was made with new host and port (127.0.0.1:port2), i.e.
     // that the explicitly specified `Host` header was cleared upon redirect.
diff --git a/test/request.js b/test/request.js
index 4747b52..9755287 100644
--- a/test/request.js
+++ b/test/request.js
@@ -1,18 +1,18 @@
-var get = require('../')
-var http = require('http')
-var test = require('tape')
+const get = require('../')
+const http = require('http')
+const test = require('tape')
 
 test('access `req` object', function (t) {
   t.plan(2)
 
-  var server = http.createServer(function (req, res) {
+  const server = http.createServer(function (req, res) {
     res.statusCode = 200
     res.end('response')
   })
 
   server.listen(0, function () {
-    var port = server.address().port
-    var req = get('http://localhost:' + port, function (err, res) {
+    const port = server.address().port
+    const req = get('http://localhost:' + port, function (err, res) {
       t.error(err)
       res.resume() // discard data
       server.close()