Page 288 - DCAP305_PRINCIPLES_OF_SOFTWARE_ENGINEERING

Principles of Software Engineering

Notes 3. Test cases that require maximum memory or other resource are executed,
4. Test cases that may cause thrashing in a virtual operating are designed,
5. Test cases that may cause excessive hunting for disk-resident are created. Essentially, the
tester attempts to break the program.
A variation of stress testing is a technique called sensitivity testing. In some situations (the
most common occur in mathematical algorithms), a very small range data contained within the
bounds of valid data for a program may cause extreme even erroneous processing or profound
performance degradation. Sensitivity attempts to uncover data combinations within valid input
classes that may work instability or improper processing.
Performance Testing

For real-time and embedded systems, software that provides required function does not conform
to performance requirements is unacceptable. Performance is designed to test the run-time
performance of software within the context of integrated system. Performance testing occurs
throughout all steps in the process. Even at the unit level, the performance of an individual
module may be assessed as white-box tests are conducted. However, it is not until all system
ele¬ments are fully integrated that the true performance of a system can be ascertained.
Performance tests are often coupled with stress testing and typically require both hardware
and software instrumentation. That is, it is often necessary to calculate resource utilization (e.g.,
processor cycles) in an exacting fashion.

Figure 14.3: The Debugging Process

Test
cases Execution
of cases
Additional
tests
Suspected Results
causes
Regression
tests
Debugging
Corrections Identified
causes

External instrumentation can monitor education intervals, log events (e.g. interrupts) as they
occur, in sample machine states on a regular basis, by incrementing a system, the tester can
uncover situations that lead to degradation and possible system failure.

Write a test case for system testing.

Top-down design was promoted in the 1970s by IBM researcher Harlan Mills
and Niklaus Wirth. Mills developed structured programming concepts for
practical use and tested them in a 1969 project to automate the New York
Times morgue index.

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