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: types_test.go
    path of file: ./repos/gitkube/vendor/golang.org/x/crypto/acme
    
    the code of the file until where you have to start completion: // Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package acme

import (
	"errors"
	"net/http"
	"testing"
	"time"
)

func TestRateLimit(t *testing.T) {
	now := time.Date(2017, 04, 27, 10, 0, 0, 0, time.UTC)
	f := timeNow
	defer func() { timeNow = f }()
	timeNow = func() time.Time { return now }

	h120, hTime := 
    
func TestRateLimit(t *testing.T) {
	now := time.Date(2017, 04, 27, 10, 0, 0, 0, time.UTC)
	f := timeNow
	defer func() { timeNow = f }()
	timeNow = func() time.Time { return now }

	h120, hTime := http.Header{}, http.Header{}
	h120.Set("Retry-After", "120")
	hTime.Set("Retry-After", "Tue Apr 27 11:00:00 2017")

	err1 := &Error{
		ProblemType: "urn:ietf:params:acme:error:nolimit",
		Header:      h120,
	}
	err2 := &Error{
		ProblemType: "urn:ietf:params:acme:error:rateLimited",
		Header:      h120,
	}
	err3 := &Error{
		ProblemType: "urn:ietf:params:acme:error:rateLimited",
		Header:      nil,
	}
	err4 := &Error{
		ProblemType: "urn:ietf:params:acme:error:rateLimited",
		Header:      hTime,
	}

	tt := []struct {
		err error
		res time.Duration
		ok  bool
	}{
		{nil, 0, false},
		{errors.New("dummy"), 0, false},
		{err1, 0, false},
		{err2, 2 * time.Minute, true},
		{err3, 0, true},
		{err4, time.Hour, true},
	}
	for i, test := range tt {
		res, ok := RateLimit(test.err)
		if ok != test.ok {
			t.Errorf("%d: RateLimit(%+v): ok = %v; want %v", i, test.err, ok, test.ok)
			continue
		}
		if res != test.res {
			t.Errorf("%d: RateLimit(%+v) = %v; want %v", i, test.err, res, test.res)
		}
	}
}