package deletemiddle_test

import (
	"testing"

	dm "git.jxs.me/leetgo/deletemiddle"
	"github.com/stretchr/testify/require"
)

func buildList(values []int) *dm.ListNode {
	var result *dm.ListNode

	for i := len(values) - 1; i >= 0; i-- {
		result = &dm.ListNode{Val: values[i], Next: result}
	}

	return result
}

func TestEmpty(t *testing.T) {
	var head *dm.ListNode
	require.Nil(t, dm.Delete(head))
}

func TestOne(t *testing.T) {
	head := buildList([]int{1})
	require.Nil(t, dm.Delete(head))
}

func TestTwo(t *testing.T) {
	head := buildList([]int{2, 1})
	expected := buildList([]int{2})
	require.Equal(t, expected, dm.Delete(head))
}

func TestFour(t *testing.T) {
	head := buildList([]int{1, 2, 3, 4})
	expected := buildList([]int{1, 2, 4})
	require.Equal(t, expected, dm.Delete(head))
}

func TestExample1(t *testing.T) {
	head := buildList([]int{1, 3, 4, 7, 1, 2, 6})
	expected := buildList([]int{1, 3, 4, 1, 2, 6})
	require.Equal(t, expected, dm.Delete(head))
}