blob: 2bc0013e20cf8302cb23f7f23711bc8f57066f96 [file] [log] [blame] [edit]
package counters
import (
"context"
"fmt"
"os"
"testing"
"time"
"github.com/stretchr/testify/require"
"go.skia.org/infra/go/gcs"
"go.skia.org/infra/go/gcs/mem_gcsclient"
"go.skia.org/infra/go/testutils"
)
// mockTime is a struct used for faking the passage of time. It keeps a current
// time which can be advanced using the Sleep or Tick methods. When either of
// the above are used, any funcs provided to AfterFunc are run if their duration
// has expired.
type mockTime struct {
t0 time.Time
t time.Time
afterFuncs map[time.Time][]func()
}
// Return a mockTime instance.
func newMockTime() *mockTime {
now := time.Now()
return &mockTime{
t0: now,
t: now,
afterFuncs: map[time.Time][]func(){},
}
}
// Equivalent to time.Now(), but returns the mocked current time.
func (t *mockTime) Now() time.Time {
return t.t
}
// Equivalent to time.AfterFunc, runs the func when the mocked current time
// passes the given duration.
func (t *mockTime) AfterFunc(d time.Duration, fn func()) *time.Timer {
runAt := t.t.Add(d)
t.afterFuncs[runAt] = append(t.afterFuncs[runAt], fn)
return nil // We don't use the returned Timer.
}
// Skip ahead the given duration and run any AfterFuncs, synchronously as
// opposed to in a goroutine, so that the caller doesn't have to wait.
func (t *mockTime) Sleep(d time.Duration) {
t.t = t.t.Add(d)
for after, funcs := range t.afterFuncs {
if t.t.After(after) {
for _, fn := range funcs {
fn()
}
delete(t.afterFuncs, after)
}
}
}
// Sleep for the given duration, then run the given func, repeatedly until
// the func returns false.
func (t *mockTime) Tick(d time.Duration, fn func() bool) {
for {
t.Sleep(d)
if !fn() {
return
}
}
}
// Return the mock elapsed time since the mockTime was created. Useful for
// debugging timelines.
func (t *mockTime) Elapsed() time.Duration {
return t.t.Sub(t.t0)
}
func TestPersistentAutoDecrementCounter(t *testing.T) {
ctx := context.Background()
gcsClient := mem_gcsclient.New("test-bucket")
mt := newMockTime()
timeAfterFunc = mt.AfterFunc
timeNowFunc = mt.Now
counters := []*PersistentAutoDecrementCounter{}
defer func() {
timeAfterFunc = time.AfterFunc
timeNowFunc = time.Now
}()
w, err := os.MkdirTemp("", "")
require.NoError(t, err)
defer testutils.RemoveAll(t, w)
f := "test_counter"
d := 200 * time.Millisecond
newCounter := func() *PersistentAutoDecrementCounter {
backingFile := fmt.Sprintf("%s_%d", f, len(counters))
if len(counters) > 0 {
// Copy the backing file from the first counter, rather
// than reusing it, to prevent contention.
firstCounterFile := fmt.Sprintf("%s_%d", f, 0)
contents, err := gcsClient.GetFileContents(ctx, firstCounterFile)
require.NoError(t, err)
require.NoError(t, gcsClient.SetFileContents(ctx, backingFile, gcs.FILE_WRITE_OPTS_TEXT, contents))
}
rv, err := NewPersistentAutoDecrementCounter(ctx, gcsClient, backingFile, d)
require.NoError(t, err)
counters = append(counters, rv)
return rv
}
c := newCounter()
require.Equal(t, int64(0), c.Get())
require.NoError(t, c.Inc(ctx))
require.Equal(t, int64(1), c.Get())
mt.Sleep(time.Duration(0.5 * float64(d)))
require.NoError(t, c.Inc(ctx))
require.Equal(t, int64(2), c.Get())
c2 := newCounter()
require.Equal(t, int64(2), c2.Get())
mt.Sleep(d)
require.Equal(t, int64(1), c.Get())
require.Equal(t, int64(1), c2.Get())
mt.Sleep(d)
require.Equal(t, int64(0), c.Get())
require.Equal(t, int64(0), c2.Get())
c3 := newCounter()
require.Equal(t, int64(0), c3.Get())
i := 0
mt.Tick(time.Duration(float64(d)/float64(4)), func() bool {
require.Equal(t, int64(i), c.Get())
require.NoError(t, c.Inc(ctx))
if i == 2 {
return false
}
i++
return true
})
mt.Sleep(time.Duration(float64(d) / float64(8)))
expect := int64(3)
mt.Tick(time.Duration(float64(d)/float64(4)), func() bool {
require.Equal(t, expect, c.Get())
c4 := newCounter()
require.Equal(t, expect, c4.Get())
if expect == 0 {
return false
}
expect--
return true
})
// Test the Reset() functionality.
require.NoError(t, c.Inc(ctx))
require.Equal(t, int64(1), c.Get())
c2 = newCounter()
require.Equal(t, int64(1), c2.Get())
require.NoError(t, c.Reset(ctx))
require.Equal(t, int64(0), c.Get())
c2 = newCounter()
require.Equal(t, int64(0), c2.Get())
// Ensure that we don't go negative or crash.
mt.Sleep(time.Duration(1.5 * float64(d)))
require.Equal(t, int64(0), c.Get())
}