validate server in link

Author: MarkRosemaker

link.go

@@ -3,6 +3,8 @@ package openapi
 import (
 	"errors"
 	"strings"
+
+	"github.com/MarkRosemaker/errpath"
 )
 
 // The `Link object` represents a possible design-time link for a response.
@@ -52,6 +54,12 @@ func (l *Link) Validate() error {
 
 	l.Description = strings.TrimSpace(l.Description)
 
+	if l.Server != nil {
+		if err := l.Server.Validate(); err != nil {
+			return &errpath.ErrField{Field: "server", Err: err}
+		}
+	}
+
 	return validateExtensions(l.Extensions)
 }
 

links_test.go

@@ -21,6 +21,13 @@ func TestLinks_Validate_Error(t *testing.T) {
 			openapi.Links{" ": {Value: &openapi.Link{}}},
 			`[" "] (" ") is invalid: must match the regular expression "^[a-zA-Z0-9\\.\\-_]+$"`,
 		},
+		{
+			openapi.Links{"foo": {Value: &openapi.Link{
+				OperationID: "myOperation",
+				Server:      &openapi.Server{},
+			}}},
+			`foo.server.url is required`,
+		},
 	} {
 		t.Run(tc.err, func(t *testing.T) {
 			if err := tc.ls.Validate(); err == nil || err.Error() != tc.err {