Improve testing, expose a bug with zero retention time

Signed-off-by: beorn7 <beorn@soundcloud.com>

silence/silence_test.go

@@ -716,7 +716,7 @@ func TestSilenceCanUpdate(t *testing.T) {
 }
 
 func TestSilenceExpire(t *testing.T) {
-	s, err := New(Options{})
+	s, err := New(Options{Retention: time.Hour})
 	require.NoError(t, err)
 
 	now := time.Now()
@@ -752,10 +752,14 @@ func TestSilenceExpire(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, 1, count)
 
-	require.NoError(t, s.expire("pending"))
-	require.NoError(t, s.expire("active"))
+	count, err = s.CountState(types.SilenceStateExpired)
+	require.NoError(t, err)
+	require.Equal(t, 1, count)
 
-	err = s.expire("expired")
+	require.NoError(t, s.Expire("pending"))
+	require.NoError(t, s.Expire("active"))
+
+	err = s.Expire("expired")
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "already expired")
 
@@ -769,10 +773,17 @@ func TestSilenceExpire(t *testing.T) {
 		UpdatedAt: now,
 	}, sil)
 
+	// Let time pass...
+	s.now = func() time.Time { return now.Add(time.Second) }
+
 	count, err = s.CountState(types.SilenceStatePending)
 	require.NoError(t, err)
 	require.Equal(t, 0, count)
 
+	count, err = s.CountState(types.SilenceStateExpired)
+	require.NoError(t, err)
+	require.Equal(t, 3, count)
+
 	// Expiring a pending Silence should make the API return the
 	// SilenceStateExpired Silence state.
 	silenceState := types.CalcSilenceState(sil.StartsAt, sil.EndsAt)
@@ -797,6 +808,72 @@ func TestSilenceExpire(t *testing.T) {
 		EndsAt:    now.Add(-time.Minute),
 		UpdatedAt: now.Add(-time.Hour),
 	}, sil)
+
+}
+
+// TestSilenceExpireWithZeroRetention covers the problem that, with zero
+// retention time, a silence explicitly set to expired will also immediately
+// expire from the silence storage.
+func TestSilenceExpireWithZeroRetention(t *testing.T) {
+	s, err := New(Options{})
+	require.NoError(t, err)
+
+	now := time.Now()
+	// But don't set s.now here because we need a changing time to
+	// demonstrate expiration from the silence storage.
+
+	m := &pb.Matcher{Type: pb.Matcher_EQUAL, Name: "a", Pattern: "b"}
+
+	s.st = state{
+		"pending": &pb.MeshSilence{Silence: &pb.Silence{
+			Id:        "pending",
+			Matchers:  []*pb.Matcher{m},
+			StartsAt:  now.Add(time.Minute),
+			EndsAt:    now.Add(time.Hour),
+			UpdatedAt: now.Add(-time.Hour),
+		}},
+		"active": &pb.MeshSilence{Silence: &pb.Silence{
+			Id:        "active",
+			Matchers:  []*pb.Matcher{m},
+			StartsAt:  now.Add(-time.Minute),
+			EndsAt:    now.Add(time.Hour),
+			UpdatedAt: now.Add(-time.Hour),
+		}},
+		"expired": &pb.MeshSilence{Silence: &pb.Silence{
+			Id:        "expired",
+			Matchers:  []*pb.Matcher{m},
+			StartsAt:  now.Add(-time.Hour),
+			EndsAt:    now.Add(-time.Minute),
+			UpdatedAt: now.Add(-time.Hour),
+		}},
+	}
+
+	count, err := s.CountState(types.SilenceStatePending)
+	require.NoError(t, err)
+	require.Equal(t, 1, count)
+
+	count, err = s.CountState(types.SilenceStateExpired)
+	require.NoError(t, err)
+	require.Equal(t, 1, count)
+
+	require.NoError(t, s.Expire("pending"))
+	require.NoError(t, s.Expire("active"))
+
+	err = s.Expire("expired")
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "already expired")
+
+	_, err = s.QueryOne(QIDs("pending"))
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "silence not found") // It is expired from the storage, too.
+
+	count, err = s.CountState(types.SilenceStatePending)
+	require.NoError(t, err)
+	require.Equal(t, 0, count)
+
+	count, err = s.CountState(types.SilenceStateExpired)
+	require.NoError(t, err)
+	require.Equal(t, 1, count) // As the two explicitly expired silences have immediately expired.
 }
 
 func TestValidateMatcher(t *testing.T) {