fixedwindow_test.go

package limiters_test

import (
	"context"
	"time"

	"github.com/google/uuid"

	l "github.com/mennanov/limiters"
)

// fixedWindows returns all the possible FixedWindow combinations.
func (s *LimitersTestSuite) fixedWindows(capacity int64, rate time.Duration, clock l.Clock) []*l.FixedWindow {
	var windows []*l.FixedWindow
	for _, inc := range s.fixedWindowIncrementers() {
		windows = append(windows, l.NewFixedWindow(capacity, rate, inc, clock))
	}
	return windows
}

func (s *LimitersTestSuite) fixedWindowIncrementers() []l.FixedWindowIncrementer {
	return []l.FixedWindowIncrementer{
		l.NewFixedWindowInMemory(),
		l.NewFixedWindowRedis(s.redisClient, uuid.New().String()),
		l.NewFixedWindowDynamoDB(s.dynamodbClient, uuid.New().String(), s.dynamoDBTableProps),
	}
}

var fixedWindowTestCases = []struct {
	capacity     int64
	rate         time.Duration
	requestCount int
	requestRate  time.Duration
	missExpected int
}{
	{
		capacity:     2,
		rate:         time.Millisecond * 100,
		requestCount: 20,
		requestRate:  time.Millisecond * 25,
		missExpected: 10,
	},
	{
		capacity:     4,
		rate:         time.Millisecond * 100,
		requestCount: 20,
		requestRate:  time.Millisecond * 25,
		missExpected: 0,
	},
	{
		capacity:     2,
		rate:         time.Millisecond * 100,
		requestCount: 15,
		requestRate:  time.Millisecond * 33,
		missExpected: 5,
	},
}

func (s *LimitersTestSuite) TestFixedWindowFakeClock() {
	clock := newFakeClockWithTime(time.Date(2019, 8, 30, 0, 0, 0, 0, time.UTC))
	for _, testCase := range fixedWindowTestCases {
		for _, bucket := range s.fixedWindows(testCase.capacity, testCase.rate, clock) {
			clock.reset()
			miss := 0
			for i := 0; i < testCase.requestCount; i++ {
				// No pause for the first request.
				if i > 0 {
					clock.Sleep(testCase.requestRate)
				}
				if _, err := bucket.Limit(context.TODO()); err != nil {
					s.Equal(l.ErrLimitExhausted, err)
					miss++
				}
			}
			s.Equal(testCase.missExpected, miss, testCase)
		}
	}
}

func (s *LimitersTestSuite) TestFixedWindowOverflow() {
	clock := newFakeClockWithTime(time.Date(2019, 8, 30, 0, 0, 0, 0, time.UTC))
	for _, bucket := range s.fixedWindows(2, time.Second, clock) {
		clock.reset()
		w, err := bucket.Limit(context.TODO())
		s.Require().NoError(err)
		s.Equal(time.Duration(0), w)
		w, err = bucket.Limit(context.TODO())
		s.Require().NoError(err)
		s.Equal(time.Duration(0), w)
		w, err = bucket.Limit(context.TODO())
		s.Require().Equal(l.ErrLimitExhausted, err)
		s.Equal(time.Second, w)
		clock.Sleep(time.Second)
		w, err = bucket.Limit(context.TODO())
		s.Require().NoError(err)
		s.Equal(time.Duration(0), w)
	}
}