[Chore] Add tests for stats

internal/stats/stats_test.go

@@ -0,0 +1,127 @@
+package stats
+
+import (
+	"math/rand"
+	"testing"
+	"time"
+)
+
+const (
+	maxCount = 10_000
+)
+
+func generateCount(t *testing.T) int64 {
+	t.Helper()
+
+	r := rand.NewSource(time.Now().UnixNano())
+	count := r.Int63() % maxCount
+	if count == 0 {
+		return 1
+	}
+
+	return count
+}
+
+func TestStats_Nil(t *testing.T) {
+	var s *Stats
+	expected := int64(0)
+	for _, inc := range []func(){
+		s.IncHits,
+		s.IncMisses,
+		s.IncHits,
+		s.IncMisses,
+	} {
+		inc()
+	}
+	for _, f := range []func() int64{
+		s.Hits,
+		s.Misses,
+		func() int64 {
+			return int64(s.Ratio())
+		},
+	} {
+		if expected != f() {
+			t.Fatalf("hits and misses for nil stats should always be %d", expected)
+		}
+	}
+	s.Clear()
+}
+
+func TestStats_Hits(t *testing.T) {
+	expected := generateCount(t)
+
+	s := New()
+	for i := int64(0); i < expected; i++ {
+		s.IncHits()
+	}
+
+	hits := s.Hits()
+	if expected != hits {
+		t.Fatalf("number of hits should be %d, but got %d", expected, hits)
+	}
+}
+
+func TestStats_Misses(t *testing.T) {
+	expected := generateCount(t)
+
+	s := New()
+	for i := int64(0); i < expected; i++ {
+		s.IncMisses()
+	}
+
+	misses := s.Misses()
+	if expected != misses {
+		t.Fatalf("number of misses should be %d, but got %d", expected, misses)
+	}
+}
+
+func TestStats_Ratio(t *testing.T) {
+	s := New()
+	ratio := s.Ratio()
+	if ratio != 0.0 {
+		t.Fatalf("ratio in stats without operations should be 0.0, but got %v", ratio)
+	}
+
+	count := generateCount(t)
+	for i := int64(0); i < count; i++ {
+		s.IncHits()
+	}
+	for i := int64(0); i < count; i++ {
+		s.IncMisses()
+	}
+
+	expected := 0.5
+	ratio = s.Ratio()
+	if expected != ratio {
+		t.Fatalf("ratio should be %v, but got %v", expected, ratio)
+	}
+}
+
+func TestStats_Clear(t *testing.T) {
+	s := New()
+
+	count := generateCount(t)
+	for i := int64(0); i < count; i++ {
+		s.IncHits()
+	}
+	for i := int64(0); i < count; i++ {
+		s.IncMisses()
+	}
+
+	misses := s.Misses()
+	if count != misses {
+		t.Fatalf("number of misses should be %d, but got %d", count, misses)
+	}
+	hits := s.Hits()
+	if count != hits {
+		t.Fatalf("number of hits should be %d, but got %d", count, hits)
+	}
+
+	s.Clear()
+
+	hits = s.Hits()
+	misses = s.Misses()
+	if hits != 0 || misses != 0 {
+		t.Fatalf("hits and misses after clear should be 0, but got hits: %d and misses: %d", hits, misses)
+	}
+}