network: Introduce constants for the network model strings

Introduce constants for the network model strings, so as to
avoid using the strings directly at multiple places.

Signed-off-by: Archana Shinde <archana.m.shinde@intel.com>

virtcontainers/network.go

@@ -68,22 +68,36 @@ func (n NetInterworkingModel) IsValid() bool {
 	return 0 <= int(n) && int(n) < int(NetXConnectInvalidModel)
 }
 
+const (
+	defaultNetModelStr = "default"
+
+	bridgedNetModelStr = "bridged"
+
+	macvtapNetModelStr = "macvtap"
+
+	enlightenedNetModelStr = "enlightened"
+
+	tcFilterNetModelStr = "tcfilter"
+
+	noneNetModelStr = "none"
+)
+
 //SetModel change the model string value
 func (n *NetInterworkingModel) SetModel(modelName string) error {
 	switch modelName {
-	case "default":
+	case defaultNetModelStr:
 		*n = DefaultNetInterworkingModel
 		return nil
-	case "bridged":
+	case bridgedNetModelStr:
 		*n = NetXConnectBridgedModel
 		return nil
-	case "macvtap":
+	case macvtapNetModelStr:
 		*n = NetXConnectMacVtapModel
 		return nil
-	case "enlightened":
+	case enlightenedNetModelStr:
 		*n = NetXConnectEnlightenedModel
 		return nil
-	case "tcfilter":
+	case tcFilterNetModelStr:
 		*n = NetXConnectTCFilterModel
 		return nil
 	case "none":

virtcontainers/network_test.go

@@ -213,12 +213,12 @@ func TestNetInterworkingModelSetModel(t *testing.T) {
 		wantErr   bool
 	}{
 		{"Invalid Model", "Invalid", true},
-		{"default Model", "default", false},
-		{"bridged Model", "bridged", false},
-		{"macvtap Model", "macvtap", false},
-		{"enlightened Model", "enlightened", false},
-		{"tcfilter Model", "tcfilter", false},
-		{"none Model", "none", false},
+		{"default Model", defaultNetModelStr, false},
+		{"bridged Model", bridgedNetModelStr, false},
+		{"macvtap Model", macvtapNetModelStr, false},
+		{"enlightened Model", enlightenedNetModelStr, false},
+		{"tcfilter Model", tcFilterNetModelStr, false},
+		{"none Model", noneNetModelStr, false},
 	}
 
 	for _, tt := range tests {