1. If the condition is a range of values, create valid test cases for each
end of the range and invalid test cases just beyond each end of the
range. For example, if a valid range of quantity on hand is -9,999
through 9,999, write test cases that include:
the valid test case quantity on hand is -9,999
the valid test case quantity on hand is 9,999
the invalid test case quantity on hand is -10,000 and
the invalid test case quantity on hand is 10,000
You may combine valid classes wherever possible, just as you did
with equivalence partitioning, and, once again, you may not combine
invalid classes. Don�t forget to consider output conditions as well. In
our inventory example the output conditions generate the following test cases:
the valid test case total quantity on hand is 0
the valid test case total quantity on hand is 999,999
the invalid test case total quantity on hand is -1 and
the invalid test case total quantity on hand is 1,000,000
2. A similar rule applies where the, condition states that the number of
values must lie within a certain range select two valid test cases, one
for each boundary of the range, and two invalid test cases, one just
below and one just above the acceptable range.
3. Design tests that highlight the first and last records in an input or
output file.
4.Look for any other extreme input or output conditions, and generate a
test for each of them.