Add test case for local in-memory fallback

go.mod

@@ -9,6 +9,9 @@ require (
 )
 
 require (
+	github.com/alicebob/gopher-json v0.0.0-20230218143504-906a9b012302 // indirect
+	github.com/alicebob/miniredis/v2 v2.33.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/yuin/gopher-lua v1.1.1 // indirect
 )

go.sum

@@ -1,3 +1,7 @@
+github.com/alicebob/gopher-json v0.0.0-20230218143504-906a9b012302 h1:uvdUDbHQHO85qeSydJtItA4T55Pw6BtAejd0APRJOCE=
+github.com/alicebob/gopher-json v0.0.0-20230218143504-906a9b012302/go.mod h1:SGnFV6hVsYE877CKEZ6tDNTjaSXYUk6QqoIK6PrAtcc=
+github.com/alicebob/miniredis/v2 v2.33.0 h1:uvTF0EDeu9RLnUEG27Db5I68ESoIxTiXbNUiji6lZrA=
+github.com/alicebob/miniredis/v2 v2.33.0/go.mod h1:MhP4a3EU7aENRi9aO+tHfTBZicLqQevyi/DJpoj6mi0=
 github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
 github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
@@ -10,5 +14,7 @@ github.com/redis/go-redis/v9 v9.6.0 h1:NLck+Rab3AOTHw21CGRpvQpgTrAU4sgdCswqGtlhG
 github.com/redis/go-redis/v9 v9.6.0/go.mod h1:hdY0cQFCN4fnSYT6TkisLufl/4W5UIXyv0b/CLO2V2M=
 github.com/redis/go-redis/v9 v9.6.1 h1:HHDteefn6ZkTtY5fGUE8tj8uy85AHk6zP7CpzIAM0y4=
 github.com/redis/go-redis/v9 v9.6.1/go.mod h1:0C0c6ycQsdpVNQpxb1njEQIqkx5UcsM8FJCQLgE9+RA=
+github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
+github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
 golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=

local_fallback_test.go

@@ -0,0 +1,70 @@
+package httprateredis_test
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/alicebob/miniredis/v2"
+	httprateredis "github.com/go-chi/httprate-redis"
+)
+
+// Test local in-memory counter fallback, which gets activated in case Redis is not available.
+func TestLocalFallback(t *testing.T) {
+	redis, err := miniredis.Run()
+	redisPort, _ := strconv.Atoi(redis.Port())
+
+	limitCounter, err := httprateredis.NewRedisLimitCounter(&httprateredis.Config{
+		Host:            redis.Host(),
+		Port:            uint16(redisPort),
+		MaxIdle:         0,
+		MaxActive:       1,
+		ClientName:      "httprateredis_test",
+		PrefixKey:       fmt.Sprintf("httprate:test:%v", rand.Int31n(100000)), // Unique Redis key for each test
+		FallbackTimeout: 200 * time.Millisecond,
+	})
+	if err != nil {
+		t.Fatalf("redis not available: %v", err)
+	}
+
+	limitCounter.Config(1000, time.Minute)
+
+	currentWindow := time.Now().UTC().Truncate(time.Minute)
+	previousWindow := currentWindow.Add(-time.Minute)
+
+	if limitCounter.IsFallbackActivated() {
+		t.Error("fallback should not be activated at the beginning")
+	}
+
+	err = limitCounter.IncrementBy("key:fallback", currentWindow, 1)
+	if err != nil {
+		t.Error(err)
+	}
+
+	_, _, err = limitCounter.Get("key:fallback", currentWindow, previousWindow)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if limitCounter.IsFallbackActivated() {
+		t.Error("fallback should not be activated before we simulate redis failure")
+	}
+
+	redis.Close()
+
+	err = limitCounter.IncrementBy("key:fallback", currentWindow, 1)
+	if err != nil {
+		t.Error(err)
+	}
+
+	_, _, err = limitCounter.Get("key:fallback", currentWindow, previousWindow)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if !limitCounter.IsFallbackActivated() {
+		t.Error("fallback should be activated after we simulate redis failure")
+	}
+}