diff --git a/integrationdhcpv4_test.go b/integrationdhcpv4_test.go
index 3eabe5b..87a7826 100644
--- a/integrationdhcpv4_test.go
+++ b/integrationdhcpv4_test.go
@@ -90,6 +90,9 @@ func TestDHCPv4(t *testing.T) {
 	if !c.ObtainOrRenew() {
 		t.Fatal(c.Err())
 	}
+	if err := c.Err(); err != nil {
+		t.Fatal(err)
+	}
 	cfg := c.Config()
 	t.Logf("cfg = %+v", cfg)
 	if got, want := cfg.Router, "192.168.23.1"; got != want {