package com.bremp.utils;

import static org.hamcrest.MatcherAssert.assertThat;

import static org.hamcrest.Matchers.is;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

import org.junit.jupiter.api.Assertions;

import org.junit.jupiter.api.DisplayName;

import org.junit.jupiter.api.Test;

import org.junit.jupiter.params.ParameterizedTest;

import org.junit.jupiter.params.provider.CsvSource;

@DisplayName("ListUtils - splitToSubLists")

class ListUtilsTest {

@Test

@DisplayName("throws exception when number of sublists is zero.")

void whenNumberOfSubListsIsZero() {

List<String> list = new ArrayList<>();

int numOfLists = 0;

Assertions.assertThrows(IllegalArgumentException.class,

() -> ListUtils.splitToSubLists(list, numOfLists));

}

@Test

@DisplayName("when list is null.")

void whenListIsNull() {

List<String> list = null;

int numOfLists = 4;

List<List<String>> actual = ListUtils.splitToSubLists(list, numOfLists);

assertThat(actual.size(), is(0));

}

@Test

@DisplayName("when list is empty.")

void whenListIsEmpty() {

List<String> list = Collections.emptyList();

int numOfLists = 1;

List<List<String>> actual = ListUtils.splitToSubLists(list, numOfLists);

assertThat(actual.size(), is(0));

}

@Test

@DisplayName("when number of sublists is greater than list size.")

void whenNumberOfSubListsIsGreaterThanListSize() {

List<String> list = Collections.singletonList("1");

int numOfLists = 2;

List<List<String>> actual = ListUtils.splitToSubLists(list, numOfLists);

assertThat(actual.size(), is(1));

}

@ParameterizedTest

@DisplayName("with varying list sizes.")

@CsvSource({

"1, 1, 1",

"'1,2', 2, 1",

"'1,2,3', 3, 1",

"'1,2,3,4', 3, 2",

"'1,2,3,4,5', 3, 2",

"'1,2,3,4,5,6', 3, 2",

"'1,2,3,4,5,6,7', 3, 3",

"'1,2,3,4,5,6,7,8', 3, 3",

"'1,2,3,4,5,6,7,8,9', 3, 3"

})

void withVaryingListSizes(String listContent, int expectedListSize, int expectedSubListSize) {

List<String> list = Arrays.asList(listContent.split(","));

int numOfLists = 3;

List<List<String>> actual = ListUtils.splitToSubLists(list, numOfLists);

actual.forEach(s -> System.out.println(s.toString()));

assertThat(actual.size(), is(expectedListSize));

assertThat(actual.get(0).size(), is(expectedSubListSize));

}

}