test(parsing): add 229 unit tests across 18 config/parsing packages

Covering nil-input safety, plugin backends (HTTP/gRPC/default), loaders
(File/HTTP/Redis), selector strategies, edge cases (empty/invalid inputs),
and hop-to-node metadata inheritance. All tests passing.

config/parsing/observer/parse_test.go

@@ -0,0 +1,75 @@
+package observer
+
+import (
+	"io"
+	"testing"
+
+	"github.com/go-gost/core/logger"
+	"github.com/go-gost/x/config"
+	xlogger "github.com/go-gost/x/logger"
+)
+
+func TestMain(m *testing.M) {
+	logger.SetDefault(xlogger.NewLogger(xlogger.OutputOption(io.Discard)))
+	m.Run()
+}
+
+func TestParseObserver_Nil(t *testing.T) {
+	obs := ParseObserver(nil)
+	if obs != nil {
+		t.Fatal("expected nil for nil config")
+	}
+}
+
+func TestParseObserver_NilPlugin(t *testing.T) {
+	obs := ParseObserver(&config.ObserverConfig{
+		Name:   "no-plugin",
+		Plugin: nil,
+	})
+	if obs != nil {
+		t.Fatal("expected nil when plugin is nil")
+	}
+}
+
+func TestParseObserver_PluginHTTP(t *testing.T) {
+	obs := ParseObserver(&config.ObserverConfig{
+		Name: "http-obs",
+		Plugin: &config.PluginConfig{
+			Type: "http",
+			Addr: "127.0.0.1:9000",
+		},
+	})
+	if obs == nil {
+		t.Fatal("expected non-nil observer")
+	}
+}
+
+func TestParseObserver_PluginGRPC(t *testing.T) {
+	obs := ParseObserver(&config.ObserverConfig{
+		Name: "grpc-obs",
+		Plugin: &config.PluginConfig{
+			Type:  "grpc",
+			Addr:  "127.0.0.1:9001",
+			Token: "secret",
+			TLS: &config.TLSConfig{
+				Secure:     true,
+				ServerName: "observer.local",
+			},
+		},
+	})
+	if obs == nil {
+		t.Fatal("expected non-nil observer")
+	}
+}
+
+func TestParseObserver_PluginDefaultType(t *testing.T) {
+	obs := ParseObserver(&config.ObserverConfig{
+		Name: "default-obs",
+		Plugin: &config.PluginConfig{
+			Addr: "127.0.0.1:9002",
+		},
+	})
+	if obs == nil {
+		t.Fatal("expected non-nil observer")
+	}
+}