I’m a fan of authors on construction whose works I can read in a programming context. On a related note, here’s a bit from Gerald Weinberg with a building/programming analogy that I like. (Quality Software Management, v. 4: Anticipating Change, pp. 216–217:
Imagine building a house by bringing all the parts to the lot, then having everybody run to the foundation and put their part in place, after which people walk around and see if the lights work or the floor collapses. There is no house test in house building to compare with the system test in system building. There are, instead, many incremental, intensive tests all throughout, especially when something is added that
- other people will depend on
- will be invisible (like wires and pipes in walls)
At every stage, the house must be stable. When it may not be, scaffolding is added so that the system of partially completed house plus scaffolding is stable. When the house becomes stable on its own, the scaffolding is taken away. Examples of scaffolding include concrete forms, extra framing, power brought to the site, and portable toilets.
Using the Stability Principle, we see that testing is not a stage, but a part of a control process embedded in everystage. What is often called system test is not a test at all, but another part of system construction, perhaps better named “system integration.” People are reworking errors in previous parts, and building the systems as they do.
Don’t get me wrong, all analogies are suspect, and I’m sure you would run into problems if you probed this one too far, but I liked it nonetheless. Incidentally, he uses “test” in a much broader sense than I normally do, including activities such as code and design reviews in the name.
I like the format of the book: it’s fairly free-form, but he frequently sprinkles in “Phrases to listen for” and “Actions to take”. The phrases in this example:
The following phrases warn a manager that the process of building while using stable phases has been or is about to be violated:
- Just wait till it’s all done, then you’ll be surprised.
- We’ll clean that up in system test.
- The testers will fix that.
- Of course we don’t have what we need, but get started anyway.
- They can clean up the design when they write the code.
- Ship it. The customers will tell us if anything is wrong.
My favorite of the phrases to listen for are those with a parenthetical note saying something like “(Warning: you may be saying this)”, as in this example from a section on fear:
- You will do this. It’s nonnegotiable. (Listen carefully: This may be coming out of your mouth.)
The point, or at least one point, of the phrases is that people’s actions are often incongruent with their beliefs and/or with stated plans and goals, and that people have a way of making statements designed to lull the listener into not realizing that. So what you should be alert to are frequently statements that are soothing on the surface, instead of statements that are alarming on the surface.
I won’t give the complete list of actions from this example; an excerpt:
DO NOT allow tests to be skipped or postponed to later stages. Whatever is pushed to the end of the cycle will be sacrificed to the schedule.
DO be aware that tests take many forms. …
In general, reasonable practical advice.
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