A Full Software Development Lifecycle Testing Project - Software Testing: Testing Across the Entire Software Development Life Cycle - page 222

Chapter 7 identifi es four functional testing techniques classifi ed as black box
testing, testing with the source code not available. These techniques are

1.
2.
3.
4.

Equivalence classes technique
Boundary value analysis technique
Expected results coverage technique
Intuition and experience

There will be ample opportunities to apply equivalence class techniques to the test-
ing of data entry screens (FTPOS-03.0, FTNEG-03.0, FTDAT-03.0, FTPOS-09.0,
FTNEG-09.0, and FTDAT-09.0). Student names and instructor names provide a
rich opportunity for testing allowable alpha and special character string classes as
a more cost-effective alternative than entering all the names in a phone book. Mail-
ing address zip codes represent another interesting test class of values. The tester
could attempt all 100,000 values in the range 00000-99999 or the tester could start
with 150 zip codes: three valid zip codes for each state (lowest, middle, and highest
value).
The DCPS will not be very rich in boundary value testing because it is neither a
true inventory control application that would have many opportunities to count and
calculate things nor a true fi nancial application with many opportunities to track
money. The two boundary value testing opportunities in the DCPS arise from the
completion student's birth date. The birth date itself offers some interesting bound-
ary value testing around days in a month, months in a year, and days in February
for leap years and leap centuries. If the developer has not already included this kind
of date component check, it is appropriate for the tester to suggest a reasonableness
check on the student birth date.
Because there is no independent way of checking the validity of the birth date
beyond confi rming that it is a legitimate calendar date, you can use an age calcula-
tion that traps at least century entry errors. For example, if the State of Colorado
does not issue driver licenses before the student age of 14, then use the input birth
date and today's system date to calculate the student's age. If the student is 13 years
old or younger, display a warning message suspecting a lower boundary birth year
error. If the State of Colorado has a cap on the age of drivers, say 80 years old, or
the State can tell you the oldest living driver, then use that age as a birth year upper
boundary warning.
One testing area of the DCPS that could benefi t from expected results test think-
ing is search screen execution (FTPOS-05.0, FTNEG-05.0, and FTDAT-05.0). A
larger class of names will be allowed for searching than for data entry, especially if
wildcard characters are permitted. For example, if you are searching for a last name
that could be spelled Smith or Smyth or Smithe, a wild card search on “Sm?h?”
should fi nd all three spellings, so should “Sm*,” but the second search criterion
would return a much longer list: every name that starts with “Sm” regardless of
the remaining letters. Related expected results issues arise between data entry and
searching of last names when the question is asked, “How are trailing blanks treated