golangci-lint undeclared name: `getProxyURL` (typecheck)

Question

Im new on golang and Im trying to _test my proxy func, the test passes correctly but when running golangci it gives me the error:

undeclared name: getProxyURL (typecheck) if got := getProxyURL(tt.args.campaignCode, urls); got != tt.want { ^

func getProxyURL(campaignCode string, urls map[string]string) string {
   if campaignURL, ok := urls[campaignCode]; ok {
      return campaignURL
   }
   return "https://facebook.com"
}

_test

package main

import "testing"

func Test_getProxyURL(t *testing.T) {
   type args struct {
      campaignCode string
   }
   urls := make(map[string]string, 0)
   urls["82383b80-056b-42e8-b192-9b0f33c4f46e"] = "https://google.com"
   urls["negativeTest"] = "https://facebook.com"

   tests := []struct {
      name string
      args args
      want string
   }{
      {
         name: "Given an invalid campaign code, we receive facebook url as result",
         args: args{campaignCode: "negativeTest"},
         want: "https://facebook.com",
      }, {
         name: "Given an valid campaign code, we receive google url as result",
         args: args{campaignCode: "82383b80-056b-42e8-b192-9b0f33c4f46e"},
         want: "https://google.com",
      },
   }

   for _, tt := range tests {
      t.Run(tt.name, func(t *testing.T) {
         if got := getProxyURL(tt.args.campaignCode, urls); got != tt.want {
            t.Errorf("getProxyURL() = %v, want %v", got, tt.want)
         }
      })
   }
}

I cant find the problem