$1.(25$ points$)$ Due to the use of polymorphism, to achieve a certain coverage

of testing we need to try all possible implementations of a function that was

overridden in subclasses. So$,$ while providing some benefits, the use of

polymorphism makes coverage testing mor difficult.

Use an example with abstract class Shape and its subclasses Circle and

Rectangle all of which have method float area$().$ Assuming the size of List

shapes remains to be $2,$ what permutations of instances of Circle and

Rectangle we have to test for due to polymorphism to achieve $100\%$ branch

coverage $?$

$...$

List shapes $=$ new ArrayList$(2)$;

$//$ list shapes is populated with any permutation of instances of Circle and$/$or Rectangle

$//$ class dynamically, say, from a user interface

float sumOfAreas $=0\mathrm{.}0$f;

for$($Shape shape : shapes$)\{$

sumOfAreas $+=$ shape.area$()$;

$\}$