初版功能完成

internal/protocol/constants_test.go

@@ -0,0 +1,66 @@
+package protocol
+
+import (
+	"testing"
+	"time"
+)
+
+func TestControlMessageTypesMatchV1Spec(t *testing.T) {
+	t.Parallel()
+	if got, want := len(ControlMessageTypes), 13; got != want {
+		t.Fatalf("ControlMessageTypes length = %d, want %d", got, want)
+	}
+	seen := make(map[ControlMessageType]struct{}, len(ControlMessageTypes))
+	for _, messageType := range ControlMessageTypes {
+		if !messageType.Valid() {
+			t.Fatalf("listed Control message type %q is invalid", messageType)
+		}
+		if _, duplicate := seen[messageType]; duplicate {
+			t.Fatalf("duplicate Control message type %q", messageType)
+		}
+		seen[messageType] = struct{}{}
+	}
+	if ControlMessageType("SESSION_RESUME").Valid() {
+		t.Fatal("non-v1 SESSION_RESUME unexpectedly accepted")
+	}
+}
+
+func TestControlEnvelopeRoundTripAndStrictPayload(t *testing.T) {
+	envelope, err := NewControlEnvelope(ControlHeartbeat, "request-1", HeartbeatPayload{
+		Timestamp: time.Date(2026, 8, 25, 0, 0, 0, 0, time.UTC), Status: "OK",
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var payload HeartbeatPayload
+	if err := envelope.DecodePayload(&payload); err != nil {
+		t.Fatal(err)
+	}
+	if payload.Status != "OK" || envelope.RequestID != "request-1" {
+		t.Fatalf("unexpected envelope: %+v payload=%+v", envelope, payload)
+	}
+	envelope.Payload = []byte(`{"timestamp":"2026-08-25T00:00:00Z","status":"OK","unknown":true}`)
+	if err := envelope.DecodePayload(&payload); err == nil {
+		t.Fatal("unknown Control payload field was accepted")
+	}
+}
+
+func TestErrorCodesMatchAuthoritativeV1List(t *testing.T) {
+	t.Parallel()
+	if got, want := len(ErrorCodes), 14; got != want {
+		t.Fatalf("ErrorCodes length = %d, want %d", got, want)
+	}
+	seen := make(map[ErrorCode]struct{}, len(ErrorCodes))
+	for _, code := range ErrorCodes {
+		if !code.Valid() {
+			t.Fatalf("listed error code %q is invalid", code)
+		}
+		if _, duplicate := seen[code]; duplicate {
+			t.Fatalf("duplicate error code %q", code)
+		}
+		seen[code] = struct{}{}
+	}
+	if ErrorCode("UNKNOWN").Valid() {
+		t.Fatal("unknown error code unexpectedly accepted")
+	}
+}