p2p/simulations: Add a sanity test case for Node.Config UnmarshalJSON

p2p/simulations/network.go

@@ -653,16 +653,16 @@ func (n *Node) MarshalJSON() ([]byte, error) {
 func (n *Node) UnmarshalJSON(raw []byte) error {
 	// TODO: How should we turn back NodeInfo into n.Node?
 	// Ticket: https://github.com/ethersphere/go-ethereum/issues/1177
-	no := struct {
+	node := struct {
 		Config *adapters.NodeConfig `json:"config,omitempty"`
 		Up     bool                 `json:"up"`
 	}{}
-	if err := json.Unmarshal(raw, &no); err != nil {
+	if err := json.Unmarshal(raw, &node); err != nil {
 		return err
 	}
 
-	n.SetUp(no.Up)
-	n.Config = no.Config
+	n.SetUp(node.Up)
+	n.Config = node.Config
 	return nil
 }
 

p2p/simulations/network_test.go

@@ -494,6 +494,12 @@ func TestNode_UnmarshalJSON(t *testing.T) {
 			runNodeUnmarshalJSON(t, casesNodeUnmarshalJSONUpField())
 		},
 	)
+	t.Run(
+		"test unmarshal of Node Config field",
+		func(t *testing.T) {
+			runNodeUnmarshalJSON(t, casesNodeUnmarshalJSONConfig())
+		},
+	)
 }
 
 func runNodeUnmarshalJSON(t *testing.T, tests []nodeUnmarshalTestCase) {
@@ -583,3 +589,34 @@ func casesNodeUnmarshalJSONUpField() []nodeUnmarshalTestCase {
 		},
 	}
 }
+
+func casesNodeUnmarshalJSONConfig() []nodeUnmarshalTestCase {
+	// Don't do a big fuss around testing, as adapters.NodeConfig should
+	// handle it's own serialization. Just do a sanity check.
+	return []nodeUnmarshalTestCase{
+		{
+			name:      "missing Config field",
+			marshaled: "{}",
+			want: Node{
+				Config: nil,
+			},
+		},
+		{
+			name:      "Config field is nil",
+			marshaled: "{\"config\": nil}",
+			want: Node{
+				Config: nil,
+			},
+		},
+		{
+			name:      "a non default Config field",
+			marshaled: "{\"config\":{\"name\":\"node_ecdd0\",\"port\":44665}}",
+			want: Node{
+				Config: &adapters.NodeConfig{
+					Name: "node_ecdd0",
+					Port: 44665,
+				},
+			},
+		},
+	}
+}