// Copyright 2024 the libevm authors.
//
// The libevm additions to go-ethereum are free software: you can redistribute
// them and/or modify them under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The libevm additions are distributed in the hope that they will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see
// <http://www.gnu.org/licenses/>.
package vm_test

import (
	"testing"

	"github.com/holiman/uint256"
	"github.com/stretchr/testify/require"

	"github.com/ethereum/go-ethereum/core/vm"
)

func TestMutableStack(t *testing.T) {
	s := &vm.Stack{}
	m := vm.MutableStack{Stack: s}

	push := func(u uint64) uint256.Int {
		u256 := uint256.NewInt(u)
		m.Push(u256)
		return *u256
	}

	require.Empty(t, s.Data(), "new stack")
	want := []uint256.Int{push(42), push(314159), push(142857)}
	require.Equalf(t, want, s.Data(), "after pushing %d values to empty stack", len(want))
	require.Equal(t, want[len(want)-1], m.Pop(), "popped value")
	require.Equal(t, want[:len(want)-1], s.Data(), "after popping a single value")
}