In the following discussion, we will examine the most commonly found schemes.
Strict inheritance is the simplest scheme of inheritance.
A derived class is a strict heir of its parent class if it keeps the exact inherited behavior of its parent. Mary Jean Harrold, John D. McGregor, and Kevin J. Fitzpatrick. Incremental testing of object-oriented class structures . May 11-15 1992. Encapsulation together with inheritance, which intuitively ought to bring a reduction in testing problems, compounds them instead.