test: remove useless code

lib/middleware/cache-common.js

@@ -1,6 +1,4 @@
 const pathToRegExp = require('path-to-regexp');
-const readall = require('readall');
-const crypto = require('crypto');
 
 const paired = (route, path) => {
     const options = {
@@ -11,24 +9,6 @@ const paired = (route, path) => {
     return pathToRegExp(route, [], options).exec(path);
 };
 
-// eslint-disable-next-line no-unused-vars
-const read = (stream) =>
-    new Promise((resolve, reject) => {
-        readall(stream, (err, data) => {
-            if (err) {
-                reject(err);
-            } else {
-                resolve(data);
-            }
-        });
-    });
-
-const md5 = (str) =>
-    crypto
-        .createHash('md5')
-        .update(str)
-        .digest('hex');
-
 const validityCheck = (routes, exclude, path) => {
     let match = false;
     let routeExpire = false;
@@ -59,7 +39,5 @@ const validityCheck = (routes, exclude, path) => {
 
 module.exports = {
     paired,
-    read,
-    md5,
     validityCheck,
 };