Pragmatic Unit Testing in Java with JUnit, 3rd Edition

Concepts as Building Blocks

One concept might be the basis for another. If you’ve provided an implementation of “capitalize a word” as a standalone method, you can incorporate it into the slightly larger concept of capitalizing all words within a sentence:

public String capitalizeAllWords(String sentence) {
  return Arrays.stream(sentence.split(" "))
    .map(this::capitalize)
    .collect(joining(" "));
}

Implementing smaller concepts as methods provides numerous benefits:

• It’s easy to derive a name that concisely summarizes the concept.
• You can re-use them in larger contexts without diminishing clarity.
• You can often digest their implementation at a glance.
• You can move them elsewhere more easily.
• You can write simpler, focused tests. ...