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: requests_test.go
    path of file: ./repos/syncthing/lib/model
    
    the code of the file until where you have to start completion: // Copyright (C) 2016 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.

package model

import (
	"bytes"
	"context"
	"errors"
	"io"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"github.com/syncthing/syncthing/lib/build"
	"github.com/syncthing/syncthing/lib/config"
	"github.com/syncthing/syncthing/lib/events"
	"github.com/syncthing/syncthing/lib/fs"
	"github.com/syncthing/syncthing/lib/protocol"
	"github.com/syncthing/syncthing/lib/rand"
)

func TestRequestSimple(t *testing.T)
    
func TestRequestLastFileProgress(t *testing.T) {
	m, fc, fcfg, wcfgCancel := setupModelWithConnection(t)
	defer wcfgCancel()
	tfs := fcfg.Filesystem(nil)
	defer cleanupModelAndRemoveDir(m, tfs.URI())

	done := make(chan struct{})

	fc.RequestCalls(func(ctx context.Context, folder, name string, blockNo int, offset int64, size int, hash []byte, weakHash uint32, fromTemporary bool) ([]byte, error) {
		defer close(done)
		progress, queued, rest, err := m.NeedFolderFiles(folder, 1, 10)
		must(t, err)
		if len(queued)+len(rest) != 0 {
			t.Error(`There should not be any queued or "rest" items`)
		}
		if len(progress) != 1 {
			t.Error("Expected exactly one item in progress.")
		}
		return fc.fileData[name], nil
	})

	contents := []byte("test file contents\n")
	fc.addFile("testfile", 0o644, protocol.FileInfoTypeFile, contents)
	fc.sendIndexUpdate()

	select {
	case <-done:
	case <-time.After(5 * time.Second):
		t.Fatal("Timed out before file was requested")
	}
}