diff --git a/layers_test.go b/layers_test.go
new file mode 100644
index 0000000..118d7b8
--- /dev/null
+++ b/layers_test.go
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2018 - present.  Boling Consulting Solutions (bcsw.net)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+package omci_test
+
+import (
+	"github.com/cboling/omci"
+	me "github.com/cboling/omci/generated"
+	"github.com/google/gopacket"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+// Note: The majority of this file is tested by other unit tests
+func TestKnownMessageTytpe(t *testing.T) {
+	for _, msg := range allMessageTypes {
+		layer, err := omci.MsgTypeToNextLayer(msg)
+		assert.NotEqual(t, layer, gopacket.LayerTypeZero)
+		assert.Nil(t, err)
+	}
+	unknown := me.MsgType(0xFF)
+	strMsg := unknown.String()
+	assert.NotEqual(t, len(strMsg), 0)
+}
+
+func TestUnknownMessageTytpe(t *testing.T) {
+	unknown := omci.MessageType(0xFF)
+	layer, err := omci.MsgTypeToNextLayer(unknown)
+	assert.Equal(t, layer, gopacket.LayerTypeZero)
+	assert.NotNil(t, err)
+}