SimpleStateBasedTestUsingStub.cs

[Fact]
public async Task ShouldClosePeriodCorrectly()
{
    // arrange
    var periodToClose = TestDataCreator.CreateTestPeriod(...);

    var periodRepository = GiveMe.StubPeriodRepository()
        .WithOneActivePeriod(periodToClose)
        .Build();

    var periodService = new PeriodService(
        periodRepository);

    // act
    await periodService.ClosePeriodAsync(periodToClose.Id);
    
    // assert
    var updatedPeriod = await periodRepository.GetPeriod(
      periodToClose.Id);
    updatedPeriod.IsActive.Should().BeFalse();
}