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: issue201_test.go
    path of file: ./repos/kin-openapi/openapi3filter
    
    the code of the file until where you have to start completion: package openapi3filter

import (
	"context"
	"io"
	"net/http"
	"strings"
	"testing"

	"github.com/stretchr/testify/require"

	"github.com/getkin/kin-openapi/openapi3"
	"github.com/getkin/kin-openapi/routers/gorillamux"
)

func TestIssue201(t *testing.T) {
	loader := openapi3.NewLoader()
	ctx := loader.Context
	spec := `
openapi: '3.0.3'
info:
  version: 1.0.0
  title: Sample API
paths:
  /_:
    get:
      description: ''
      responses:
        default:
          description: ''
          content:
            application/json:
              schema:
                type: object
          headers:
            X-Blip:
              description: ''
              required: true
              schema:
                type: string
                pattern: '^blip$'
            x-blop:
              description: ''
              schema:
                type: string
                pattern: '^blop$'
            X-Blap:
              description: ''
              required: true
              schema:
                type: string
                pattern: '^blap$'
            X-Blup:
              description: ''
              required: true
              schema:
                type: string
                patt
    
func TestIssue201(t *testing.T) {
	loader := openapi3.NewLoader()
	ctx := loader.Context
	spec := `
openapi: '3.0.3'
info:
  version: 1.0.0
  title: Sample API
paths:
  /_:
    get:
      description: ''
      responses:
        default:
          description: ''
          content:
            application/json:
              schema:
                type: object
          headers:
            X-Blip:
              description: ''
              required: true
              schema:
                type: string
                pattern: '^blip$'
            x-blop:
              description: ''
              schema:
                type: string
                pattern: '^blop$'
            X-Blap:
              description: ''
              required: true
              schema:
                type: string
                pattern: '^blap$'
            X-Blup:
              description: ''
              required: true
              schema:
                type: string
                pattern: '^blup$'
`[1:]

	doc, err := loader.LoadFromData([]byte(spec))
	require.NoError(t, err)

	err = doc.Validate(ctx)
	require.NoError(t, err)

	for name, testcase := range map[string]struct {
		headers map[string]string
		err     string
	}{

		"no error": {
			headers: map[string]string{
				"X-Blip": "blip",
				"x-blop": "blop",
				"X-Blap": "blap",
				"X-Blup": "blup",
			},
		},

		"missing non-required header": {
			headers: map[string]string{
				"X-Blip": "blip",
				// "x-blop": "blop",
				"X-Blap": "blap",
				"X-Blup": "blup",
			},
		},

		"missing required header": {
			err: `response header "X-Blip" missing`,
			headers: map[string]string{
				// "X-Blip": "blip",
				"x-blop": "blop",
				"X-Blap": "blap",
				"X-Blup": "blup",
			},
		},

		"invalid required header": {
			err: `response header "X-Blup" doesn't match schema: string doesn't match the regular expression "^blup$"`,
			headers: map[string]string{
				"X-Blip": "blip",
				"x-blop": "blop",
				"X-Blap": "blap",
				"X-Blup": "bluuuuuup",
			},
		},
	} {
		t.Run(name, func(t *testing.T) {
			router, err := gorillamux.NewRouter(doc)
			require.NoError(t, err)

			r, err := http.NewRequest(http.MethodGet, `/_`, nil)
			require.NoError(t, err)

			r.Header.Add(headerCT, "application/json")
			for k, v := range testcase.headers {
				r.Header.Add(k, v)
			}

			route, pathParams, err := router.FindRoute(r)
			require.NoError(t, err)

			err = ValidateResponse(context.Background(), &ResponseValidationInput{
				RequestValidationInput: &RequestValidationInput{
					Request:    r,
					PathParams: pathParams,
					Route:      route,
				},
				Status: 200,
				Header: r.Header,
				Body:   io.NopCloser(strings.NewReader(`{}`)),
			})
			if e := testcase.err; e != "" {
				require.ErrorContains(t, err, e)
			} else {
				require.NoError(t, err)
			}
		})
	}
}