add extra check to make sure the downloaded jar file is not corrupt

Author: delabiejochen

lib/tunnel-launcher.js

@@ -1,6 +1,7 @@
 'use strict'
 
 const async = require('async')
+const { exec } = require('child_process')
 const fs = require('fs')
 const os = require('os')
 const path = require('path')
@@ -25,13 +26,24 @@ function download (options, callback) {
     }
 
     try {
-        const tunnelFile = fs.statSync(tunnelLocation)
-        if (tunnelFile['size'] > 1024) {
-            return callback(null)
+        const exists = fs.existsSync(tunnelLocation)
+        if (exists) {
+            return exec(`java -jar ${tunnelLocation} -h`, (error, stdout, stderr) => {
+                if (error || stderr) {
+                    logger('Found a cached testingbot-tunnel.jar file, but it might be corrupt. Redownloading.')
+                    downloadTunnel(url, tunnelLocation, callback)
+                } else {
+                    callback(null)
+                }
+            })
         }
     } catch (ignore) {}
 
-    downloader.get(url, { fileName: 'testingbot-tunnel', destination: tunnelLocation }, (err, destination) => {
+    return downloadTunnel(url, tunnelLocation, callback)
+}
+
+function downloadTunnel (url, tunnelLocation, callback) {
+    downloader.get(url, { fileName: 'testingbot-tunnel', destination: tunnelLocation }, (err) => {
         if (err) {
             return callback(new Error(`Could not download the tunnel from TestingBot - please check your connection. ${err.message}`))
         }