diff --git a/test/async.js b/test/async.js
index b307650..e5c4c4d 100644
--- a/test/async.js
+++ b/test/async.js
@@ -8,7 +8,7 @@ const valid = require('./fixtures/har/valid')
 const validate = require('../lib/async')
 
 tap.test('async', assert => {
-  let keys = Object.keys(schemas).filter(key => key !== 'default')
+  const keys = Object.keys(schemas).filter(key => key !== 'default')
 
   assert.plan(keys.length)
 
@@ -20,7 +20,7 @@ tap.test('async', assert => {
 tap.test('failure', assert => {
   assert.plan(4)
 
-  let error = new HARError([{ dataPath: '.log.version', message: 'should be string' }])
+  const error = new HARError([{ dataPath: '.log.version', message: 'should be string' }])
 
   assert.notOk(validate.har({}), 'should fail')
 
diff --git a/test/promise.js b/test/promise.js
index 60e05c0..71071a8 100644
--- a/test/promise.js
+++ b/test/promise.js
@@ -7,7 +7,7 @@ const tap = require('tap')
 const validate = require('../lib/promise')
 
 tap.test('promises', assert => {
-  let keys = Object.keys(schemas).filter((key) => key !== 'default')
+  const keys = Object.keys(schemas).filter((key) => key !== 'default')
 
   assert.plan((keys.length * 2) + 2)