Programming and Problem Solving with Java

11.2 List Class | 537

The methodslength,insert, anddeletemust be tested together. That is, we insert
several items and check the length; we delete several items and check the length. How do
we know that theinsertanddeleteoperations work correctly? We must write an auxil-
iary methodprintListthat iterates through the list usinglengthandgetNextItemto print
out the values. We callprintListto check the status of the list after a series of insertions
and deletions. To test theisFulloperation, we must test it when the list is full and when
it is not. We must also callinsertwhen the list is full to confirm that the list remains
unchanged.
Do we need to test any special cases for deleteand isThere? We look first at the end
cases. What are the end cases in a list? The item is in the first position in the list, the item is
in the last position in the list, and the item is the only one in the list. We must verify that delete
can correctly delete items in these positions. We must check that isTherecan find items in
these same positions and correctly determine that values are not in the list.
These observations are summarized in the following test plan. The tests are shown in
the order in which they should be performed.

Operation to Be Tested and
Description of Action Input Values Expected Output Observed Output

Constructor (4)

print length

insert

insertfour items and print

insertitem and print

isThere

isTheresusy and print whether found

isThere maryand print whether found

isThere annand print whether found

isThere bettyand print whether found

isFull

invoke (list is full)

delete annand invoke

delete

print

delete bettyand print

delete maryand print

delete johnand print

isEmpty

mary,john,ann,betty

sarah

0

mary,john,ann,betty

mary,john,ann,betty

item is not found

item is found

item is found

item is found

list is full

list is not full

mary,john,betty

mary,john

john

(empty)

yes