public void long_interval_for_easy_cards()
{
var difficultyRating = DifficultyRating.Easiest;
var daysSincePreviousReview = 11;
var item = new ReviewItemBuilder()
.WithLastReviewDate(_clock.Now().AddDays(-1))
.WitPreviousReviewDate(daysSincePreviousReview)
.WithDifficultyRating(difficultyRating)
.WithCorrectReviewStreak(3)
.Build();
var strategy = new SuperMemo2ReviewStrategy(_clock);
var nextReview = strategy.NextReview(item);
var expectedInterval = (daysSincePreviousReview - 1) * strategy.DifficultyRatingToEasinessFactor(difficultyRating);
Assert.That(nextReview, Is.EqualTo(item.ReviewDate.AddDays(expectedInterval)));
}