better-unit-test-in-c#-article-PutInsideTest-full.cs

better-unit-test-in-c#-article-PutInsideTest-full.cs

public static class PutInsideTest
{
  public sealed record Args
  {
    public Thing Thing { get; init; } = null!;
    public string Label { get; init; } = "";
  }

  sealed class TestCases : IEnumerable<object[]>
  {
    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

    public IEnumerator<object[]> GetEnumerator()
    {
      yield return OpenBox_ThingFitIntoBoxAndUniqueLabel_ThingAddedIntoBox_TrueExpected_1();
      yield return ClosedBox_ThingFitIntoBoxAndUniqueLabel_ThingNotAddedIntoBox_FalseExpected_2();
    }

    static object[] OpenBox_ThingFitIntoBoxAndUniqueLabel_ThingAddedIntoBox_TrueExpected_1()
    {
      var stateActual = new Box(
        new Dictionary<string, Thing>
        {
          { "Label1", new Thing { Size = 10 } },
          { "Label2", new Thing { Size = 20 } },
        })
      {
        Size = 100,
        IsOpen = true
      };

      var args = new Args
      {
        Thing = new Thing { Size = 30 },
        Label = "Label3"
      };

      var stateExpected = new Box(new Dictionary<string, Thing>
      {
        { "Label1", new Thing { Size = 10 } },
        { "Label2", new Thing { Size = 20 } },
        { "Label3", new Thing { Size = 30 } },
      })
      {
        Size = 100,
        IsOpen = true
      };

      var expected = true;

      return new object[] { stateActual, args, stateExpected, expected };
    }

    static object[] ClosedBox_ThingFitIntoBoxAndUniqueLabel_ThingNotAddedIntoBox_FalseExpected_2()
    {
      var stateActual = new Box(
        new Dictionary<string, Thing>
        {
          { "Label1", new Thing { Size = 10 } },
          { "Label2", new Thing { Size = 20 } },
        })
      {
        Size = 100,
        IsOpen = false
      };

      var args = new Args
      {
        Thing = new Thing { Size = 30 },
        Label = "Label3"
      };

      var stateExpected = new Box(
        new Dictionary<string, Thing>
        {
          { "Label1", new Thing { Size = 10 } },
          { "Label2", new Thing { Size = 20 } },
        })
      {
        Size = 100,
        IsOpen = false
      };

      var expected = true;

      return new object[] { stateActual, args, stateExpected, expected };
    }
  }

  [Theory]
  [ClassData(typeof(TestCases))]
  public static void Test(
    Box stateActual,
    Args args,
    Box stateExpected,
    bool expected)
  {
    var actual = stateActual.PutInside(args.Thing, args.Label);

    Assert.Equal(stateExpected, stateActual);
    Assert.Equal(expected, actual);
  }
}