Troubleshooting

This section presents some of the common pitfalls you might face when using specs2 and Scala

vals vs lazy vals

The common symptom here is a NullPointerException for some attributes of your specification. You can refer to this link for an explanation of variable initialization in Scala. In the meantime the basic fix is to use a lazy val instead of a val.

Lost expectations

You might expect the following specification to fail:

class ShouldItFail extends Specification:
  def is = s2"""
  Should this example fail? $e1
  """

  def e1 =
    1 must ===(100000) // do you expect this to fail
    10 must ===(10)

However, as explained in Structure - Thrown expectations, the first expectation is lost because, by default, no exceptions are thrown in an acceptance specification. In that case you can either:

• create 2 examples having one expectation each
• mix-in the ThrownExpectations trait
  
  

Custom output

You created a custom Notifier or another class for reporting and when you use it nothing happens. In that case add the verbose argument to the command line and you will get more messages including exceptions and stacktraces about what is going on.