public void GivenCollection_WhenAddingManyTags_ThenCountIsIncreasedByThatNumberAndContains(int number) { // Arrange var oldCount = _tags.GetCount <string>(); // Act _tags.AddMany <string>(number); var newCount = _tags.GetCount <string>(); // Assert Assert.That(newCount, Is.EqualTo(oldCount + number)); Assert.That(_tags.Contains <string>()); }