fix: handle empty servers list in oas3 spec when getting baseUrl (#1310)

Author: dtkav

src/execute/index.js

@@ -270,7 +270,7 @@ function oas3BaseUrl({spec, pathName, method, server, contextUrl, serverVariable
   let selectedServerUrl = ''
   let selectedServerObj = null
 
-  if (server && servers) {
+  if (server && servers && servers.length) {
     const serverUrls = servers.map(srv => srv.url)
 
     if (serverUrls.indexOf(server) > -1) {
@@ -279,7 +279,7 @@ function oas3BaseUrl({spec, pathName, method, server, contextUrl, serverVariable
     }
   }
 
-  if (!selectedServerUrl && servers) {
+  if (!selectedServerUrl && servers && servers.length) {
     // default to the first server if we don't have one by now
     selectedServerUrl = servers[0].url
     selectedServerObj = servers[0]

test/oas3/execute/main.js

@@ -755,6 +755,20 @@ describe('buildRequest - OpenAPI Specification 3.0', function () {
 
       expect(res).toEqual('http://google.com')
     })
+    it('should fall back to contextUrls if servers list is empty', function () {
+      const spec = {
+        openapi: '3.0.0',
+        servers: []
+      }
+
+      const res = baseUrl({
+        spec,
+        server: 'http://some-invalid-server.com/',
+        contextUrl: 'http://google.com/'
+      })
+
+      expect(res).toEqual('http://google.com')
+    })
     it('should create a relative url based on a relative server if no contextUrl is available', function () {
       const spec = {
         openapi: '3.0.0',