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scalaexceptionspecs2

Specs2: detect exception in implicitly-converted val assignment

I have code that looks like this, to detect an NPE in an assignment. The assignment triggers an implicit conversion in which the NPE happens (it implicitly converts from a CoreRecommendedDomain to an APIRecommededDomain:

"ensure Scala RecommendedDomain from null must throw NPE" in {
  val n: CoreRecommendedDomain = null
  var r: APIRecommendedDomain = APIRecommendedDomain("example.com")
  (r = n) must throwA[NullPointerException]
}

The above code works. But, of course, I'd rather not have to create a dummy APIRecommendedDomain into a var only to test assignment. I'd much rather detect the NPE when I do something like:

val r: APIRecommendedDomain = n

I can't seem to find how to do this short of wrapping the whole thing in a try/catch. That kinda defeats the more elegant syntax, though.

Or am I out of luck?

Solution

  • You can assign a type to null directly, this should trigger the implicit conversion:

    "ensure Scala RecommendedDomain from null must throw NPE" in {
  ((null: CoreRecommendedDomain): APIRecommendedDomain) must throwA[NullPointerException]
}