public void TestClearNotifiesObservers()
{
CoinPurse coinPurse = new CoinPurse();
MockCoin mockCoin = new MockCoin();
MockCoinPurseObserver mockCoinPurseObserver = new MockCoinPurseObserver();
coinPurse.RegisterObserver(mockCoinPurseObserver);
coinPurse.Clear();
Assert.AreEqual(1, mockCoinPurseObserver.NumberOfTimesCoinPurseUpdatedCalled);
}
public void TestClearReturnsAllCoinsAndEmptiesPurse()
{
CoinPurse coinPurse = new CoinPurse();
MockCoin mockCoin = new MockCoin();
coinPurse.AddCoin(mockCoin);
List<ICoin> coinsReturnedFromClear = coinPurse.Clear();
Assert.AreEqual(1, coinsReturnedFromClear.Count);
Assert.AreEqual(mockCoin, coinsReturnedFromClear[0]);
Assert.AreEqual(0, coinPurse.Coins.Count);
}