diff --git a/package.json b/package.json
index e4c812b..313396e 100644
--- a/package.json
+++ b/package.json
@@ -59,11 +59,11 @@
     "url-parse-lax": "^1.0.0"
   },
   "devDependencies": {
-    "ava": "^0.12.0",
+    "ava": "^0.13.0",
     "coveralls": "^2.11.4",
     "get-port": "^2.0.0",
     "into-stream": "^2.0.0",
-    "nyc": "^5.0.1",
+    "nyc": "^6.0.0",
     "pem": "^1.4.4",
     "pify": "^2.3.0",
     "tempfile": "^1.1.1",
diff --git a/test/https.js b/test/https.js
index a603eac..01945b5 100644
--- a/test/https.js
+++ b/test/https.js
@@ -5,9 +5,6 @@ import got from '../';
 import {createSSLServer} from './helpers/server';
 
 let s;
-let key;
-let cert;
-let caRootKey;
 let caRootCert;
 
 const pemP = pify(pem, Promise);
@@ -15,7 +12,7 @@ const pemP = pify(pem, Promise);
 test.before('setup', async () => {
 	const caKeys = await pemP.createCertificate({days: 1, selfSigned: true});
 
-	caRootKey = caKeys.serviceKey;
+	const caRootKey = caKeys.serviceKey;
 	caRootCert = caKeys.certificate;
 
 	const keys = await pemP.createCertificate({
@@ -31,8 +28,8 @@ test.before('setup', async () => {
 		commonName: 'sindresorhus.com'
 	});
 
-	key = keys.clientKey;
-	cert = keys.certificate;
+	const key = keys.clientKey;
+	const cert = keys.certificate;
 
 	s = await createSSLServer({key, cert});
 
diff --git a/test/redirects.js b/test/redirects.js
index dba2d91..ceceb27 100644
--- a/test/redirects.js
+++ b/test/redirects.js
@@ -6,18 +6,14 @@ import {createServer, createSSLServer} from './helpers/server';
 
 let http;
 let https;
-let key;
-let cert;
-let caRootKey;
-let caRootCert;
 
 const pemP = pify(pem, Promise);
 
 test.before('setup', async () => {
 	const caKeys = await pemP.createCertificate({days: 1, selfSigned: true});
 
-	caRootKey = caKeys.serviceKey;
-	caRootCert = caKeys.certificate;
+	const caRootKey = caKeys.serviceKey;
+	const caRootCert = caKeys.certificate;
 
 	const keys = await pemP.createCertificate({
 		serviceCertificate: caRootCert,
@@ -32,8 +28,8 @@ test.before('setup', async () => {
 		commonName: 'sindresorhus.com'
 	});
 
-	key = keys.clientKey;
-	cert = keys.certificate;
+	const key = keys.clientKey;
+	const cert = keys.certificate;
 
 	https = await createSSLServer({key, cert});