all: add tests, imp code

contextutil/contextutil.go

@@ -6,7 +6,7 @@ import (
 	"time"
 )
 
-// Constructor is an interface for constructing interfaces with deadlines, e.g.
+// Constructor is an interface for constructing contexts with deadlines, e.g.
 // for request contexts.
 type Constructor interface {
 	// New returns a new context based on parent as well as a cancel function.

contextutil/contextutil_test.go

@@ -0,0 +1,24 @@
+package contextutil_test
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/golibs/contextutil"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTimeoutConstructor(t *testing.T) {
+	const timeout = 1 * time.Minute
+
+	c := contextutil.NewTimeoutConstructor(timeout)
+	ctx, cancel := c.New(context.Background())
+	defer cancel()
+
+	dl, ok := ctx.Deadline()
+	assert.True(t, ok)
+
+	d := time.Until(dl)
+	assert.InDelta(t, timeout, d, float64(1*time.Second))
+}

testutil/sentrytest/sentrytest.go

@@ -1,5 +1,7 @@
 // Package sentrytest contains fake implementations of interfaces for the Sentry
 // module.
+//
+// TODO(a.garipov):  Add more utilities or rename to fakesentry.
 package sentrytest
 
 import (
@@ -43,6 +45,9 @@ func (t *Transport) SendEvent(e *sentry.Event) {
 // NewTransport returns a new *Transport all methods of which panic.
 func NewTransport() (tst *Transport) {
 	return &Transport{
+		OnClose: func() {
+			panic(fmt.Errorf("unexpected call to sentrytest.(*Transport).Close()"))
+		},
 		OnConfigure: func(opts sentry.ClientOptions) {
 			panic(fmt.Errorf("unexpected call to sentrytest.(*Transport).Configure(%v)", opts))
 		},

timeutil/schedule.go

@@ -69,7 +69,7 @@ var _ Schedule = (*CronSchedule)(nil)
 
 // UntilNext implements the [Schedule] interface for *CronSchedule.
 func (s *CronSchedule) UntilNext(now time.Time) (d time.Duration) {
-	return max(time.Until(s.cron.Next(now)), 0)
+	return max(s.cron.Next(now).Sub(now), 0)
 }
 
 // RandomizedSchedule adds a random duration to the result of the [Schedule]

timeutil/schedule_test.go

@@ -0,0 +1,52 @@
+package timeutil_test
+
+import (
+	"math/rand/v2"
+	"testing"
+	"time"
+
+	"github.com/AdguardTeam/golibs/timeutil"
+	"github.com/robfig/cron/v3"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConstSchedule(t *testing.T) {
+	const ivl = 5 * time.Minute
+	s := timeutil.NewConstSchedule(ivl)
+
+	now := time.Now()
+	d := s.UntilNext(now)
+	assert.Equal(t, ivl, d)
+}
+
+func TestCronSchedule(t *testing.T) {
+	p := cron.NewParser(cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow)
+	cs, err := p.Parse("*/5 * * * *")
+	require.NoError(t, err)
+
+	s := timeutil.NewCronSchedule(cs)
+
+	now := time.Now()
+	for range 100_000 {
+		d := s.UntilNext(now)
+		assert.InDelta(t, 5*time.Minute, d, float64(5*time.Minute))
+	}
+}
+
+func TestRandomizedSchedule(t *testing.T) {
+	const (
+		ivl    = 5 * time.Minute
+		minAdd = -1 * time.Minute
+		maxAdd = 1 * time.Minute
+	)
+
+	now := time.Now()
+	r := rand.New(rand.NewPCG(uint64(now.Unix()), 0))
+	s := timeutil.NewRandomizedSchedule(timeutil.NewConstSchedule(ivl), r, minAdd, maxAdd)
+
+	for range 100_000 {
+		d := s.UntilNext(now)
+		assert.InDelta(t, ivl, d, float64(2*time.Minute))
+	}
+}