diff --git a/internal/qos/grpc_test.go b/internal/qos/grpc_test.go
index d6e2a689c..d4030c39e 100644
--- a/internal/qos/grpc_test.go
+++ b/internal/qos/grpc_test.go
@@ -19,6 +19,7 @@ const (
 
 var (
 	errTest         = errors.New("mock")
+	errWrongTag     = errors.New("wrong tag")
 	errResExhausted *apistatus.ResourceExhausted
 )
 
@@ -119,3 +120,18 @@ func Test_MaxActiveRPCLimiter(t *testing.T) {
 		require.True(t, lim.released)
 	})
 }
+
+func TestSetCriticalIOTagUnaryServerInterceptor_Pass(t *testing.T) {
+	interceptor := qos.NewSetCriticalIOTagUnaryServerInterceptor()
+	called := false
+	handler := func(ctx context.Context, req any) (any, error) {
+		called = true
+		if tag, ok := tagging.IOTagFromContext(ctx); ok && tag == qos.IOTagCritical.String() {
+			return nil, nil
+		}
+		return nil, errWrongTag
+	}
+	_, err := interceptor(context.Background(), nil, nil, handler)
+	require.NoError(t, err)
+	require.True(t, called)
+}