You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: issue341_test.go
    path of file: ./repos/kin-openapi/openapi3
    
    the code of the file until where you have to start completion: package openapi3

import (
	"context"
	"testing"

	"github.com/stretchr/testify/require"
)

func TestIssue341(t *testing.T) {
	sl := NewLoader()
	sl.IsExternalRefsAllowed = true
	doc, err := sl.LoadFromFile("testdata/main.yaml")
	require.NoError(t, err)


    
func TestIssue341(t *testing.T) {
	sl := NewLoader()
	sl.IsExternalRefsAllowed = true
	doc, err := sl.LoadFromFile("testdata/main.yaml")
	require.NoError(t, err)

	err = doc.Validate(sl.Context)
	require.NoError(t, err)

	err = sl.ResolveRefsIn(doc, nil)
	require.NoError(t, err)

	bs, err := doc.MarshalJSON()
	require.NoError(t, err)
	require.JSONEq(t, `{
	"info": {
		"title": "test file",
		"version": "n/a"
	},
	"openapi": "3.0.0",
	"paths": {
		"/testpath": {
			"$ref": "testpath.yaml#/paths/~1testpath"
		}
	}
}`, string(bs))

	require.Equal(t, &Types{"string"}, doc.
		Paths.Value("/testpath").
		Get.
		Responses.Value("200").Value.
		Content["application/json"].
		Schema.Value.
		Type)

	doc.InternalizeRefs(context.Background(), nil)
	bs, err = doc.MarshalJSON()
	require.NoError(t, err)
	require.JSONEq(t, `{
		"components": {
		  "responses": {
			"testpath_200_response": {
			  "content": {
				"application/json": {
				  "schema": {
					"type": "string"
				  }
				}
			  },
			  "description": "a custom response"
			}
		  }
		},
		"info": {
		  "title": "test file",
		  "version": "n/a"
		},
		"openapi": "3.0.0",
		"paths": {
		  "/testpath": {
			"get": {
			  "responses": {
				"200": {
				  "$ref": "#/components/responses/testpath_200_response"
				}
			  }
			}
		  }
		}
	  }`, string(bs))
}