with surviving mutants

GildedRoseTest.java

package com.gildedrose;

import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.Test;

public class GildedRoseTest {


  private static final int MIN_QUALITY = 0;
  private static final int MAX_QUALITY = 50;

  @Test
  public void regular_items_quality_decreases_every_day() {
    Item item = regularItem(1, 3);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(2, item.quality);
    assertEquals(0, item.sellIn);
  }

  @Test
  public void expired_regular_items_quality_decreases_twice_as_fast_once_sellIn_has_passed() {
    Item item = regularItem(0, 3);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(1, item.quality);
    assertEquals(-1, item.sellIn);
  }

  @Test
  public void regular_items_quality_never_decreases_below_the_minimum_quality() {
    Item item = regularItem(5, 0);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(MIN_QUALITY, item.quality);
    assertEquals(4, item.sellIn);
  }

  @Test
  public void aged_brie_increases_quality_by_1() {
    Item item = agedBrie(5, 8);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(9, item.quality);
    assertEquals(4, item.sellIn);
  }

  @Test
  public void aged_brie_quality_never_increases_over_the_maximun_quality() {
    Item item = agedBrie(5, MAX_QUALITY);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(MAX_QUALITY, item.quality);
    assertEquals(4, item.sellIn);
  }

  @Test
  public void expired_aged_brie_increases_quality_by_2() {
    Item item = agedBrie(0, 8);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(10, item.quality);
    assertEquals(-1, item.sellIn);
  }

  @Test
  public void sulfuras_never_changes() {
    Item item = sulfuras(1, 80);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(80, item.quality);
    assertEquals(1, item.sellIn);
  }

  @Test
  public void expired_sulfuras_never_changes() {
    Item item = sulfuras(-1, 80);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(80, item.quality);
    assertEquals(-1, item.sellIn);
  }

  @Test
  public void backstage_increase_quality_by_1_when_sellIn_is_greater_than_10() {
    Item item = backstagePasses(11, 6);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(7, item.quality);
    assertEquals(10, item.sellIn);
  }

  @Test
  public void backstage_increase_quality_by_2_when_sellIn_is_between_10_and_6() {
    Item item1 = backstagePasses(8, 6);
    GildedRose shop = new GildedRose(new Item[]{item1});

    shop.updateQuality();

    assertEquals(8, item1.quality);
    assertEquals(7, item1.sellIn);
  }

  @Test
  public void backstage_increase_quality_by_3_when_sellIn_is_between_5_and_1() {
    Item item1 = backstagePasses(4, 6);
    GildedRose shop = new GildedRose(new Item[]{item1});

    shop.updateQuality();

    assertEquals(9, item1.quality);
    assertEquals(3, item1.sellIn);
  }

  @Test
  public void backstage_quality_drops_to_0_after_the_concert() {
    Item item = backstagePasses(0, 6);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(MIN_QUALITY, item.quality);
    assertEquals(-1, item.sellIn);
  }

  @Test
  public void backstage_quality_never_increases_over_the_maximun_quality() {
    Item item = backstagePasses(11, MAX_QUALITY);
    GildedRose shop = new GildedRose(new Item[]{item});

    shop.updateQuality();

    assertEquals(MAX_QUALITY, item.quality);
    assertEquals(10, item.sellIn);
  }

  public Item regularItem(int sellIn, int quality) {
    return new Item("foo", sellIn, quality);
  }

  public Item agedBrie(int sellIn, int quality) {
    return new Item("Aged Brie", sellIn, quality);
  }

  public Item sulfuras(int sellIn, int quality) {
    return new Item("Sulfuras, Hand of Ragnaros", sellIn, quality);
  }

  public Item backstagePasses(int sellIn, int quality) {
    return new Item("Backstage passes to a TAFKAL80ETC concert", sellIn, quality);
  }
}