fix(azure-function): handle single or multiple cookies at once (#525)

* Fix Azure Cookie - Handle single or multiple cookies at once

headers['set-cookie'] can be a string of one cookie, or an array of cookies
headerCookies should always be an array

* Fix tests - No more "response.cookies: []" when no cookie

Sorry about that

Co-authored-by: Brett Andrews <brett.j.andrews@gmail.com>

src/event-sources/azure/http-function-runtime-v3.js

@@ -42,11 +42,13 @@ function getResponseToHttpFunction ({ statusCode, body, headers = {}, isBase64En
   }
 
   const cookies = []
-  const headerCookies = headers['set-cookie']
-
+  // headers['set-cookie'] can be a string of one cookie, or an array of cookies
+  // headerCookies should always be an array
+  const headerCookies = [].concat(headers['set-cookie'] || [])
+
   // Convert 'set-cookie' to Azure Function 3.x cookie object array
   // https://github.com/Azure/azure-functions-nodejs-worker/blob/v3.x/types/index.d.ts#L150
-  if (headerCookies) {
+  if (headerCookies.length > 0) {
     for (const headerCookie of headerCookies) {
       const parsedCookie = parseCookie(headerCookie)
       const nameValueTuple = headerCookie.split(';')[0].split('=')