1 files changed, 142 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/filter/bloom_test.go b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/filter/bloom_test.go
new file mode 100644
index 000000000..1fb56f071
--- /dev/null
+++ b/Godeps/_workspace/src/github.com/syndtr/goleveldb/leveldb/filter/bloom_test.go
@@ -0,0 +1,142 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package filter
+
+import (
+	"encoding/binary"
+	"github.com/syndtr/goleveldb/leveldb/util"
+	"testing"
+)
+
+type harness struct {
+	t *testing.T
+
+	bloom     Filter
+	generator FilterGenerator
+	filter    []byte
+}
+
+func newHarness(t *testing.T) *harness {
+	bloom := NewBloomFilter(10)
+	return &harness{
+		t:         t,
+		bloom:     bloom,
+		generator: bloom.NewGenerator(),
+	}
+}
+
+func (h *harness) add(key []byte) {
+	h.generator.Add(key)
+}
+
+func (h *harness) addNum(key uint32) {
+	var b [4]byte
+	binary.LittleEndian.PutUint32(b[:], key)
+	h.add(b[:])
+}
+
+func (h *harness) build() {
+	b := &util.Buffer{}
+	h.generator.Generate(b)
+	h.filter = b.Bytes()
+}
+
+func (h *harness) reset() {
+	h.filter = nil
+}
+
+func (h *harness) filterLen() int {
+	return len(h.filter)
+}
+
+func (h *harness) assert(key []byte, want, silent bool) bool {
+	got := h.bloom.Contains(h.filter, key)
+	if !silent && got != want {
+		h.t.Errorf("assert on '%v' failed got '%v', want '%v'", key, got, want)
+	}
+	return got
+}
+
+func (h *harness) assertNum(key uint32, want, silent bool) bool {
+	var b [4]byte
+	binary.LittleEndian.PutUint32(b[:], key)
+	return h.assert(b[:], want, silent)
+}
+
+func TestBloomFilter_Empty(t *testing.T) {
+	h := newHarness(t)
+	h.build()
+	h.assert([]byte("hello"), false, false)
+	h.assert([]byte("world"), false, false)
+}
+
+func TestBloomFilter_Small(t *testing.T) {
+	h := newHarness(t)
+	h.add([]byte("hello"))
+	h.add([]byte("world"))
+	h.build()
+	h.assert([]byte("hello"), true, false)
+	h.assert([]byte("world"), true, false)
+	h.assert([]byte("x"), false, false)
+	h.assert([]byte("foo"), false, false)
+}
+
+func nextN(n int) int {
+	switch {
+	case n < 10:
+		n += 1
+	case n < 100:
+		n += 10
+	case n < 1000:
+		n += 100
+	default:
+		n += 1000
+	}
+	return n
+}
+
+func TestBloomFilter_VaryingLengths(t *testing.T) {
+	h := newHarness(t)
+	var mediocre, good int
+	for n := 1; n < 10000; n = nextN(n) {
+		h.reset()
+		for i := 0; i < n; i++ {
+			h.addNum(uint32(i))
+		}
+		h.build()
+
+		got := h.filterLen()
+		want := (n * 10 / 8) + 40
+		if got > want {
+			t.Errorf("filter len test failed, '%d' > '%d'", got, want)
+		}
+
+		for i := 0; i < n; i++ {
+			h.assertNum(uint32(i), true, false)
+		}
+
+		var rate float32
+		for i := 0; i < 10000; i++ {
+			if h.assertNum(uint32(i+1000000000), true, true) {
+				rate++
+			}
+		}
+		rate /= 10000
+		if rate > 0.02 {
+			t.Errorf("false positive rate is more than 2%%, got %v, at len %d", rate, n)
+		}
+		if rate > 0.0125 {
+			mediocre++
+		} else {
+			good++
+		}
+	}
+	t.Logf("false positive rate: %d good, %d mediocre", good, mediocre)
+	if mediocre > good/5 {
+		t.Error("mediocre false positive rate is more than expected")
+	}
+}