package main

import (
	"reflect"
	"testing"
)

func TestAdder(t *testing.T) {
	assertCorrectMessage := func(t testing.TB, sum, expect int) {
		if sum != expect {
			t.Errorf("expected %d but got %d", sum, expect)
		}
	}

	t.Run("2 + 2", func(t *testing.T) {
		numbers := []int{2, 2}
		sum := Add(numbers)
		expect := 4
		assertCorrectMessage(t, sum, expect)
	})

	t.Run("1 + 1", func(t *testing.T) {
		numbers := []int{1, 1}
		sum := Add(numbers)
		expect := 2
		assertCorrectMessage(t, sum, expect)
	})

	t.Run("1 + 2 + 3 + 4 + 5", func(t *testing.T) {
		numbers := []int{1, 2, 3, 4, 5}
		sum := Add(numbers)
		expect := 15
		assertCorrectMessage(t, sum, expect)
	})
}

func TestAdderSlice(t *testing.T) {
	got := SumAll([]int{1, 2}, []int{0, 9})
	want := []int{3, 9}

	// this is not type safe
	if !reflect.DeepEqual(got, want) {
		t.Errorf("got %v want %v", got, want)
	}
}

func TestSumAllTails(t *testing.T) {
	checkSums := func(t testing.TB, got, want []int) {
		t.Helper()
		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %v want %v", got, want)
		}
	}
	t.Run("make the some of some slices", func(t *testing.T) {
		got := SumAllTails([]int{1, 2}, []int{0, 9})
		want := []int{2, 9}
		checkSums(t, got, want)
	})

	t.Run("safely sum empty slices", func(t *testing.T) {
		got := SumAllTails([]int{}, []int{3, 4, 5})
		want := []int{0, 9}
		checkSums(t, got, want)
	})
}