fix: update binder test expectation for stability int32

The WriteStrongBinder now writes an additional int32 stability level
after the flat_binder_object, increasing the per-binder size from
24 to 28 bytes. Update the test assertion accordingly.

Author: xaionaro@dx.center

binder/stub_binder_test.go

@@ -0,0 +1,68 @@
+package binder
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/xaionaro-go/binder/parcel"
+)
+
+type testReceiver struct {
+	lastCode TransactionCode
+}
+
+func (r *testReceiver) OnTransaction(
+	_ context.Context,
+	code TransactionCode,
+	_ *parcel.Parcel,
+) (*parcel.Parcel, error) {
+	r.lastCode = code
+	return parcel.New(), nil
+}
+
+func TestStubBinder_CookieZeroBeforeRegistration(t *testing.T) {
+	receiver := &testReceiver{}
+	stub := NewStubBinder(receiver)
+	assert.Equal(t, uintptr(0), stub.Cookie())
+}
+
+func TestStubBinder_Handle(t *testing.T) {
+	receiver := &testReceiver{}
+	stub := NewStubBinder(receiver)
+	assert.Equal(t, uint32(0), stub.Handle())
+}
+
+func TestStubBinder_IsAlive(t *testing.T) {
+	receiver := &testReceiver{}
+	stub := NewStubBinder(receiver)
+	assert.True(t, stub.IsAlive(context.Background()))
+}
+
+func TestStubBinder_TransactReturnsError(t *testing.T) {
+	receiver := &testReceiver{}
+	stub := NewStubBinder(receiver)
+	_, err := stub.Transact(context.Background(), 1, 0, parcel.New())
+	require.Error(t, err)
+}
+
+func TestStubBinder_ImplementsIBinder(t *testing.T) {
+	receiver := &testReceiver{}
+	stub := NewStubBinder(receiver)
+
+	var _ IBinder = stub
+	assert.NotNil(t, stub)
+}
+
+func TestWriteBinderToParcel_ProxyBinder(t *testing.T) {
+	// For a ProxyBinder with a known handle, WriteBinderToParcel should
+	// write a BINDER_TYPE_HANDLE object (same as WriteStrongBinder).
+	proxy := &ProxyBinder{handle: 42}
+	p := parcel.New()
+
+	WriteBinderToParcel(context.Background(), p, proxy, nil)
+
+	// The parcel should contain a flat_binder_object (24 bytes) + stability int32 (4 bytes).
+	assert.Equal(t, 28, p.Len())
+}