Pragmatic Unit Testing in Java with JUnit, 3rd Edition

Increasing Your ROI: Cleaning Up Tests

Always review your tests for opportunities to improve their readability. A few minutes of cleanup now can save countless developers from far more head-scratching time down the road.

Review your CreditHistory test. See if you can spot ways to improve things.

Scannability: Arrange—Act—Assert

With but four lines, your test is already a mass of code demanding close attention:

utj3-credit-history/06/src/test/java/credit/ACreditHistory.java

@Test
void withOneRatingHasEquivalentMean() {
   var creditHistory = new CreditHistory();
   creditHistory.add(new CreditRating(780));
   var result = creditHistory.arithmeticMean();
   assertEquals(780, result);
}

The test has little scannability (as Mike Hill calls ...