package mergesorted_test

import (
	"testing"

	ms "git.jxs.me/leetgo/mergesorted"
	"github.com/stretchr/testify/require"
)

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

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

	return result
}

func TestEmpty(t *testing.T) {
	require.Nil(t, nil, ms.MergeTwoLists(nil, nil))
}

func TestEmptyRight(t *testing.T) {
	left := buildList([]int{4, 5})
	right := buildList([]int{})
	res := ms.MergeTwoLists(left, right)
	require.Equal(t, left, res)
}

func TestEmptyLeft(t *testing.T) {
	left := buildList([]int{})
	right := buildList([]int{1, 2})
	res := ms.MergeTwoLists(left, right)
	require.Equal(t, right, res)
}

func TestMix(t *testing.T) {
	left := buildList([]int{1, 3})
	right := buildList([]int{2, 4})
	res := ms.MergeTwoLists(left, right)

	expected := buildList([]int{1, 2, 3, 4})
	require.Equal(t, expected, res)
}

func TestExample1(t *testing.T) {
	left := buildList([]int{1, 3, 4})
	right := buildList([]int{1, 2, 4})
	res := ms.MergeTwoLists(left, right)

	expected := buildList([]int{1, 1, 2, 3, 4, 4})
	require.Equal(t, expected, res)
}

func TestExample2(t *testing.T) {
	left := buildList([]int{})
	right := buildList([]int{0})
	res := ms.MergeTwoLists(left, right)

	expected := buildList([]int{0})
	require.Equal(t, expected, res)
}