test Get panic when no store, update readme

Author: dsa0x

bloom.go

@@ -83,49 +83,6 @@ func NewBloom(err_rate float64, capacity int, database Store) *BloomFilter {
 	}
 }
 
-func NewBloomWithK(err_rate float64, capacity int, database Store, k int) *BloomFilter {
-	if err_rate <= 0 || err_rate >= 1 {
-		panic("Error rate must be between 0 and 1")
-	}
-	if capacity < 0 {
-		panic("Capacity must be greater than 0")
-	}
-
-	// P
-	err_rate /= 100.0
-
-	// number of hash functions (k)
-	numHashFn := int(math.Ceil(math.Log2(1.0 / err_rate)))
-	if k > 0 {
-		numHashFn = int(k)
-	}
-
-	//ln22 = ln2^2
-	ln22 := math.Pow(math.Ln2, 2)
-
-	// M
-	bit_width := int(math.Ceil((float64(capacity) * math.Abs(math.Log(err_rate))) /
-		ln22))
-	//m
-	bits_per_slice := bit_width / numHashFn
-
-	seeds := make([]int64, numHashFn)
-
-	for i := 0; i < len(seeds); i++ {
-		seeds[i] = int64((i + 1) << 16)
-	}
-
-	return &BloomFilter{
-		err_rate:  err_rate,
-		capacity:  capacity,
-		bit_width: bit_width,
-		bit_array: make([]bool, bit_width),
-		m:         bits_per_slice,
-		seeds:     seeds,
-		db:        database,
-	}
-}
-
 func NewBloomFromFile(path string) {
 
 }
@@ -159,7 +116,7 @@ func (bf *BloomFilter) Find(key []byte) bool {
 // Get Gets the key from the underlying persistent store
 func (bf *BloomFilter) Get(key []byte) []byte {
 	if !bf.hasStore() {
-		return nil
+		log.Panicf("BloomFilter has no persistent store. Use Find() instead")
 	}
 
 	if !bf.Find(key) {

bloom_test.go

@@ -80,6 +80,21 @@ func TestBloomFilter_Add(t *testing.T) {
 		bf.Add([]byte("test"), []byte("bar"))
 		t.Errorf("Expected function to panic when number of entries exceed the capacity")
 	})
+
+	t.Run("get should panic when there is no persistent store", func(t *testing.T) {
+		defer func() {
+			if r := recover(); r == nil {
+				fmt.Println("recovered from panic")
+				return
+			}
+		}()
+
+		count := 100
+		bf := NewBloom(0.1, count, nil)
+		bf.Add([]byte("foo"), []byte("bar"))
+		val := bf.Get([]byte("foo"))
+		t.Errorf("Expected function to panic when there is no persistent store, got %s", val)
+	})
 }
 func TestBloomFilter_AddToDB(t *testing.T) {
 	store, cleanupFunc := DBSetupTest(t)

readme.md

@@ -78,6 +78,11 @@ import (
 )
 
 func main() {
+
+	bf := gobloomgo.NewScalableBloom(0.01, 100, nil)
+	bf.Find([]byte("foo"))
+
+	// with a persistent store
 	opts := badger.DefaultOptions("/tmp/bloom.db")
 	db := gobloomgo.NewBadger(opts)
 	bf := gobloomgo.NewScalableBloom(0.9, 100, db)