How to test a Try[T] with ScalaTest correctly?

12
votes

I have a method that returns a Try object:

def doSomething(p: SomeParam): Try[Something] = {
  // code
}

I now want to test this with ScalaTest. Currently I am doing it like this:

"My try method" should "succeed" in {
  val maybeRes = doSomething(SomeParam("foo"))
  maybeRes.isSuccess shouldBe true
  val res = maybeRes.get
  res.bar shouldBe "moo"
}

However checking for isSuccess to be true looks a bit clumsy because for Options and Sequences there are things like should be(empty) and shouldNot be(empty). I cannot find anything like should be(successful).

Does this exist or is my approach really the way to go?

3
scalascalatest

3 Answers

22
votes

Another possibility is to do 

import org.scalatest.TryValues._
maybeRes.success.value.bar shouldBe "moo"

This will give a message indicating the Try was not a success, instead of throwing the exception in maybeRes.get.

The analog exist for Option, Either and PartialFunction (using the relevant import)

12
votes

Just check to see that it is the success type with your return value:

maybeRes shouldBe Success("moo")
2
votes

Alternatively

import org.scalatest.TryValues._

// ... 

maybeRes.success.value should be "moo"