Why Is Unit Testing So Hard? - Example 2 Refactored Tests

example-2_refactored-tests_why-is-unit-testing-so-hard.cs

public class PlayerTest
{
  private Weapon _weapon;
  private IPowerup _powerup;

  [SetUp]
  public void Init()
  {
    _weapon = Substitute.For<Weapon>();
    _weapon.Damage.Returns(1);
    _powerup = Substitute.For<IPowerup>();
    _powerup.Multiplier.Returns(2);
  }
  
  [Test]
  public void PowerupDamage()
  {
    for (var i = 1; i < 5; i++)
    {
      var player = new Player(_weapon);
      for (var j = 0; j < i; j++)
      {
        player.Powerups.Add(_powerup);
      }
      Assert.AreEqual(CalculateDamage(player.Powerups), player.Damage);
    }
  }
  
  private double CalculateDamage(IEnumerable<IPowerup> powerups)
  {
    return _weapon.Damage * powerups.Sum(p => p.Multiplier);
  }