Absence of Errors Fallacy

Though copious errors guarantee worthlessness, zero errors says nothing about the value of software. This is Gerald Weinberg's "Absence of Errors Fallacy." It really puts testing into perspective. It also puts all software engineering and management into perspective. The first part of the principle is obviously true; software with many errors is useless. The second part provides food for thought. It says that, no matter how hard you work to remove errors, you are wasting your time unless you are building the right system. Akao's Quality Function Deployment provides details on one method of ensuring that you are building the right system throughout the live cycle. A corollary to this principle is that all the formal methods, all the testing, and all the product assurance in the world won't help if you are building the wrong system.


Reference:
Weinberg, G., Quality Software Management, Vol. 1: Systems Thinking, New York: Dorset House, 1992.

Shakedown

Doctor Who: Shakedown by Terrance Dicks
My rating: 4 of 5 stars

Can you really have a Doctor Who story that is not about Doctor Who? Yes! In fact, this story is certainly better for having so little focus on the Doctor.

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Doctor Who: The Mind of Evil

Doctor Who: The Mind of Evil by Terrance Dicks
My rating: 3 of 5 stars

The BBC Audio is from the television soundtrack which leaves a fair amount of detail out. It is okay if you are a Doctor Who fan and know who the characters are but in no way should it be considered a standalone book.

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When to Rob a Bank

When to Rob a Bank by Steven D. Levitt
My rating: 3 of 5 stars

There are a few gems in here that should be revisited and reframed for today. There is also a lot that was only relevant in the past. Overall, it is worth reading but maybe with an eye to skipping anything that seems overly out-of-date.

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Wayne of Gotham

Wayne of Gotham by Tracy Hickman
My rating: 2 of 5 stars

While reading this book I felt that there was too much everything. The crazy people were too crazy. The rich people were too snobbish and blind. Batman was too paranoid.

And yet, after finishing and thinking back on it I cannot come up with a better way of handling the story. The crazy people only seem too crazy because fragmented and false memories really do leave people making no sense. And maybe rich people really are snobs and blind to the world beyond their money. And Batman being paranoid is not a new theme and why wouldn't it just get worse as he gets older?!

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Testing Exposes Presence Of Flaws

No matter how through, testing simply exposes the presence of flaws in a program; it cannot be used to verify the absence of flaws. It can increase your confidence that a program is correct, but it cannot prove correctness. To gain true correctness, one must use completely different processes, that is, correctness proofs.


Reference:
Dijkstra, E., "Notes on Structured Programming," in Structured Programming, Dahl, O., et al., Academic Press, 1972.

Don't Write Your Own Test Plans

Not only should you not be the sole tester of your own software, but you should also not be responsible for generating the test data, test scenarios, or test plans for your software. If you are, you may make the same mistakes in test generation that you made in software creation. For example, if you made a false assumption about the range of legal inputs when engineering the software, you would likely make the same assumption when generating test plans.

If you are a programmer and/or designer and your manager has asked you to write your test plans, I recommend you switch the test plan generation responsibility with a fellow programmer and/or designer. If you are a member of a requirements engineering team, with responsibility for system test generation as well, I recommend that members of your team subdivide the responsibilities so that no individual generates tests for requirements that she or he wrote.

Don't Test Your Own Software

Software developers should never be the primary testers of their own software. It is certainly appropriate to do initial debugging and unit testing.

Independent testers are necessary:

1. To check a unit for adequacy before starting integration testing.
2. For all integration testing.
3. For all system testing.

The correct attitude during testing is that of wanting to expose bugs. How can a developer possibly embrace that attitude? Testing is difficult enough without burdening it further with testers who have a bias toward no finding bugs.

Reference:

Myers, G., The Art of Software Testing, New York: John Wiley & Sons, 1979.

Plan Tests Long Before It Is Time To Test

Often software developers create their software product, then scratch their heads and say, "Now, how are we going to test this thing?" Test planning is a major task and must occur in parallel with product development so that test planning and initial (that is, pretesting) development activities are completed in synchrony.

For software system testing, test planners should review the SRS for testability before it is baselined and provide feedback to requirements writers. Serious development of the tests should start soon after baselining requirements. For integrations testing, test planners should review the preliminary design before it is baselined. They should also provide feedback to the project managers and designers concerning (1) sensible allocations of resources to ensure that the "right" components (from a testing point of view) are produced in the right order and (2) modifications to the design to make it inherently easier to test. Serious integration test development should start soon after baselining the preliminary design. For unit testing, unit test plan development can start immediately after the completion of detailed design.


Reference:
Goodenough, J., and Gerhart, S., "Toward a Theory of Test Data Selection," IEEE Transactions on Software Engineering, June 1975.

It's Superman

It's Superman! by Tom De Haven
My rating: 3 of 5 stars

I enjoyed Tom De Haven's writing style and the story was good. But there were too many liberties taken with the idea of Superman for me to really enjoy it. De Haven puts a heavy gloss of reality on the story of Superman and sets the origin story in the 30s.

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