fix: Catch the exit of the server process (#104)

Fail immediately if the server cannot be started because the
server process failed to start

Close #89

package.json

@@ -75,6 +75,7 @@
     "start-with-child": "node test/server-as-child.js",
     "start-multiple": "node test/multiple-servers.js",
     "start-https": "node test/https-server.js",
+    "start-fail": "node test/server-fail.js",
     "test2": "curl http://127.0.0.1:9000",
     "test3": "curl http://127.0.0.1:9000 && curl http://127.0.0.1:9001",
     "test4": "curl --insecure https://127.0.0.1:9000",
@@ -87,6 +88,7 @@
     "demo7": "node bin/start.js :9000 test2",
     "demo8": "node bin/start.js start-multiple \":9000|:9001\" test3",
     "demo9": "node bin/start.js start-https \"https://127.0.0.1:9000\" test4",
+    "demo10": "node bin/start.js start-fail http://127.0.0.1:9000 test",
     "travis-deploy-once": "travis-deploy-once"
   },
   "devDependencies": {

src/index.js

@@ -46,6 +46,12 @@ function startAndTest ({ start, url, test }) {
   }
 
   const waited = new Promise((resolve, reject) => {
+    const onClose = () => {
+      reject(new Error('server closed unexpectedly'))
+    }
+
+    server.on('close', onClose)
+
     debug('starting waitOn %s', url)
     waitOn(
       {
@@ -63,6 +69,7 @@ function startAndTest ({ start, url, test }) {
           return reject(err)
         }
         debug('waitOn finished successfully')
+        server.removeListener('close', onClose)
         resolve()
       }
     )

test/server-fail.js

@@ -0,0 +1,13 @@
+const http = require('http');
+const server = http.createServer((req, res) => {
+  console.log(req.method)
+  if (req.method === 'GET') {
+    res.end('All good\n\n')
+  } else {
+    res.end();
+  }
+});
+setTimeout(() => {
+  process.exit(1)
+}, 5000)
+console.log('sleeping for 5 seconds before starting')