public void TestMultiply()
{
var c = new MockCalculator(_resultWriter);
var result = c.Multiply(3, 2);
Assert.Equal(result, 6);
}
public void TestException()
{
var mock = new Mock <IResultWriter>();
mock.Setup(o => o.WriteResult(It.IsAny <double>())).Throws(new IOException("Disk is full"));
var c = new MockCalculator(mock.Object);
Assert.Throws <IOException>(() => c.Multiply(3, 2));
}