test: add a delay after starting the npm registry

Attempt at improving test reliability on CI

package.json

@@ -41,6 +41,7 @@
     "codecov": "^3.0.0",
     "commitizen": "^2.9.6",
     "cz-conventional-changelog": "^2.0.0",
+    "delay": "^2.0.0",
     "dockerode": "^2.5.2",
     "eslint-config-prettier": "^2.5.0",
     "eslint-plugin-prettier": "^2.3.0",

test/helpers/npm-registry.js

@@ -1,6 +1,7 @@
 import Docker from 'dockerode';
 import getStream from 'get-stream';
 import got from 'got';
+import delay from 'delay';
 import pRetry from 'p-retry';
 
 const IMAGE = 'npmjs/npm-docker-couchdb:1.6.1';
@@ -28,6 +29,7 @@ async function start() {
   });
 
   await container.start();
+  await delay(3000);
 
   try {
     // Wait for the registry to be ready