package cache import (	"errors"	"fmt"	"testing"	"time" 	"github.com/stretchr/testify/assert"	"github.com/stretchr/testify/require") var (	called      = 0	errSentinel = errors.New("an error")	errCached   = errors.New("a cached error")) func setup(t *testing.T) (*Cache, CreateFunc) {	called = 0	create := func(path string) (interface{}, bool, error) {		assert.Equal(t, 0, called)		called++		switch path {		case "/":			return "/", true, nil		case "/file.txt":			return "/file.txt", true, errCached		case "/error":			return nil, false, errSentinel		}		panic(fmt.Sprintf("Unknown path %q", path))	}	c := New()	return c, create} func TestGet(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, len(c.cache)) 	f, err := c.Get("/", create)	require.NoError(t, err) 	assert.Equal(t, 1, len(c.cache)) 	f2, err := c.Get("/", create)	require.NoError(t, err) 	assert.Equal(t, f, f2)} func TestGetFile(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, len(c.cache)) 	f, err := c.Get("/file.txt", create)	require.Equal(t, errCached, err) 	assert.Equal(t, 1, len(c.cache)) 	f2, err := c.Get("/file.txt", create)	require.Equal(t, errCached, err) 	assert.Equal(t, f, f2)} func TestGetError(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, len(c.cache)) 	f, err := c.Get("/error", create)	require.Equal(t, errSentinel, err)	require.Equal(t, nil, f) 	assert.Equal(t, 0, len(c.cache))} func TestPut(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, len(c.cache)) 	c.Put("/alien", "slime") 	assert.Equal(t, 1, len(c.cache)) 	fNew, err := c.Get("/alien", create)	require.NoError(t, err)	require.Equal(t, "slime", fNew) 	assert.Equal(t, 1, len(c.cache))} func TestCacheExpire(t *testing.T) {	c, create := setup(t) 	c.expireInterval = time.Millisecond	assert.Equal(t, false, c.expireRunning) 	_, err := c.Get("/", create)	require.NoError(t, err) 	c.mu.Lock()	entry := c.cache["/"] 	assert.Equal(t, 1, len(c.cache))	c.mu.Unlock()	c.cacheExpire()	c.mu.Lock()	assert.Equal(t, 1, len(c.cache))	entry.lastUsed = time.Now().Add(-c.expireDuration - 60*time.Second)	assert.Equal(t, true, c.expireRunning)	c.mu.Unlock()	time.Sleep(250 * time.Millisecond)	c.mu.Lock()	assert.Equal(t, false, c.expireRunning)	assert.Equal(t, 0, len(c.cache))	c.mu.Unlock()} func TestClear(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, len(c.cache)) 	_, err := c.Get("/", create)	require.NoError(t, err) 	assert.Equal(t, 1, len(c.cache)) 	c.Clear() 	assert.Equal(t, 0, len(c.cache))} func TestEntries(t *testing.T) {	c, create := setup(t) 	assert.Equal(t, 0, c.Entries()) 	_, err := c.Get("/", create)	require.NoError(t, err) 	assert.Equal(t, 1, c.Entries()) 	c.Clear() 	assert.Equal(t, 0, c.Entries())} func TestGetMaybe(t *testing.T) {	c, create := setup(t) 	value, found := c.GetMaybe("/")	assert.Equal(t, false, found)	assert.Nil(t, value) 	f, err := c.Get("/", create)	require.NoError(t, err) 	value, found = c.GetMaybe("/")	assert.Equal(t, true, found)	assert.Equal(t, f, value) 	c.Clear() 	value, found = c.GetMaybe("/")	assert.Equal(t, false, found)	assert.Nil(t, value)}