Adding Human-Readable Information

Log messages

We’ve met many different ScalaTest tools so far, allowing us to assert a wide range of properties using two testing styles (assertions and matchers). However, we haven’t focused on log messages. Log messages are also very important for testing code, although not as important in applicative code. Our tests do complex operations and assert many properties, so logging information can be useful. Also, we can display information to clarify what’s being done during the test.

We can do that in three ways. The most obvious is using println statements. It works but fits poorly in the test output, as we’ll see shortly. ScalaTest offers two better ways: Informers and GivenWhenThen. In this lesson, we’ll explore these three ways.

The println statements

The most basic way of printing information during the execution of our tests is by using println statements. The following example retrofits the EducativeSpec class, adding println statements.