fix: reset condition in burst sampler (#711) (#712)

Author: crazy-pe

sampler.go

@@ -90,7 +90,7 @@ func (s *BurstSampler) inc() uint32 {
 	now := TimestampFunc().UnixNano()
 	resetAt := atomic.LoadInt64(&s.resetAt)
 	var c uint32
-	if now > resetAt {
+	if now >= resetAt {
 		c = 1
 		atomic.StoreUint32(&s.counter, c)
 		newResetAt := now + s.Period.Nanoseconds()

sampler_test.go

@@ -1,3 +1,4 @@
+//go:build !binary_log
 // +build !binary_log
 
 package zerolog
@@ -103,3 +104,34 @@ func BenchmarkSamplers(b *testing.B) {
 		})
 	}
 }
+
+func TestBurst(t *testing.T) {
+	sampler := &BurstSampler{Burst: 1, Period: time.Second}
+
+	t0 := time.Now()
+	now := t0
+	mockedTime := func() time.Time {
+		return now
+	}
+
+	TimestampFunc = mockedTime
+	defer func() { TimestampFunc = time.Now }()
+
+	scenario := []struct {
+		tm   time.Time
+		want bool
+	}{
+		{t0, true},
+		{t0.Add(time.Second - time.Nanosecond), false},
+		{t0.Add(time.Second), true},
+		{t0.Add(time.Second + time.Nanosecond), false},
+	}
+
+	for i, step := range scenario {
+		now = step.tm
+		got := sampler.Sample(NoLevel)
+		if got != step.want {
+			t.Errorf("step %d (t=%s): expect %t got %t", i, step.tm, step.want, got)
+		}
+	}
+}