public void TestAddBall()
{
// Arrange:
// Create the fake stockFeed:
var fakePerson = A.Fake <IPerson>();
IStudent student = new Student();
// Act:
A.CallTo(() => fakePerson.Age).Returns(15);
A.CallTo(() => fakePerson.Name).Returns("Dima");
student.Person = fakePerson;
student.AddBall(3.5);
// Assert:
Assert.AreEqual(3.5d, student.avgBall);
Assert.AreEqual(fakePerson, student.Person);
}