computer science

Self-testing code

Self-testing code is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Self-testing code rather than just read about it. In short: Self-testing code is software that incorporates built-in tests (see test-first development). Perl packages will run their self tests when they are installed using CPAN.

Key takeaways

Self-testing code belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Self-testing code to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Self-testing code from memory before moving on to harder problems.

Reference excerpt

Self-testing code is software that incorporates built-in tests (see test-first development).

Perl packages will run their self tests when they are installed using CPAN. This ensures that they run successfully in the local environment. (There is also a testing community that tests new packages and updated packages on many different platforms.) In Java, to execute a unit test from the command line, a class can have methods like the following.

To invoke a full system test, a class can incorporate a method call.

In addition, Java has some Jupiter API libraries for self-testing code. assert can be used in various ways such as assert equals, which checks if the given variable is equal to the value given.

See also Software development Extreme programming

References

Worked examples

Example 1 — a first encounter with Self-testing code

Start with the simplest possible case. Write down what Self-testing code claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Self-testing code before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Self-testing code ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Self-testing code

In research: Self-testing code appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Self-testing code in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Self-testing code is common in secondary-school and first-year university syllabi. It links to neighbouring topics Software engineering stubs, Unit testing, so understanding it makes those chapters shorter.
In everyday life: Look for Self-testing code outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Self-testing code in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Self-testing code means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Self-testing code out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Self-testing code in simple terms?

Self-testing code is software that incorporates built-in tests (see test-first development). Perl packages will run their self tests when they are installed using CPAN.

Why does Self-testing code matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Self-testing code?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Self-testing code.