Added tests and readme

internal/config/node_test.go

@@ -0,0 +1,58 @@
+package config
+
+import "testing"
+
+func TestAdvertiseAddrFallback(t *testing.T) {
+	cases := []struct {
+		name      string
+		cfg       NodeConfig
+		want      string
+	}{
+		{"explicit advertise wins", NodeConfig{Advertise: "host:1234", BindAddr: "0.0.0.0", BindPort: 9001}, "host:1234"},
+		{"empty bind falls back to loopback", NodeConfig{BindPort: 9001}, "127.0.0.1:9001"},
+		{"wildcard bind falls back to loopback", NodeConfig{BindAddr: "0.0.0.0", BindPort: 9001}, "127.0.0.1:9001"},
+		{"ipv6 wildcard falls back to loopback", NodeConfig{BindAddr: "::", BindPort: 9001}, "127.0.0.1:9001"},
+		{"specific bind preserved", NodeConfig{BindAddr: "10.0.0.1", BindPort: 9001}, "10.0.0.1:9001"},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := tc.cfg.AdvertiseAddr(); got != tc.want {
+				t.Errorf("got %q want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestNodeConfigRoundtrip(t *testing.T) {
+	t.Setenv("QUPTIME_DIR", t.TempDir())
+	n := &NodeConfig{NodeID: "abc", BindAddr: "127.0.0.1", BindPort: 9001, Advertise: "10.0.0.1:9001"}
+	if err := n.Save(); err != nil {
+		t.Fatal(err)
+	}
+	loaded, err := LoadNodeConfig()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if *loaded != *n {
+		t.Errorf("got %+v want %+v", *loaded, *n)
+	}
+}
+
+func TestLoadNodeConfigAppliesDefaults(t *testing.T) {
+	t.Setenv("QUPTIME_DIR", t.TempDir())
+	// Save with empty bind addr/port to verify Load fills them.
+	n := &NodeConfig{NodeID: "abc"}
+	if err := n.Save(); err != nil {
+		t.Fatal(err)
+	}
+	loaded, err := LoadNodeConfig()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if loaded.BindPort != 9001 {
+		t.Errorf("BindPort=%d want 9001", loaded.BindPort)
+	}
+	if loaded.BindAddr != "0.0.0.0" {
+		t.Errorf("BindAddr=%q want 0.0.0.0", loaded.BindAddr)
+	}
+}