Testing Right[Seq[MyClass]] and properties

Question

I am trying to implement a test with ScalaTest (WordSpecLike, MustMatchers) that verify if an Either[Seq[Error], Seq[Value]] contains one value and if the value has some specific attributes.

Ideally I would like to have something like:

val result:Either[Seq[Error], Seq[Value]] = ...
result.value must contain { _ have (
  'prop ("value")
)}

But this does not compile and I have no clue on how to achieve this kind of matching.

Is there documentation on deep tests or some best practices for that?

Answer 1

Inspectors enable assertions to be made about collections, and in combination with EitherValues, as suggested by @LuisMiguelMejíaSuárez, and checking arbitrary properties with have, the following syntax is possible

atLeast(1, result.right.value) must have ('prop ("value"))

Here is a working example

class Value(val foo: String, val bar: Int) {
  def isTooLong: Boolean = foo.length > 2
}

class StackOverflowSpec extends WordSpec with MustMatchers with EitherValues with Inspectors {
  "Result" when {
    "Right" should {
      "have property" in {
        val result: Either[Seq[Error], Seq[Value]] = Right(Seq(new Value("aa", 11), new Value("bbb", 42)))
        atLeast(1, result.right.value) must have ('tooLong (true), 'bar (42) )
      }
    }
  }
}

Alternatively try pattern matching on result and passing the property predicate to Seq.exists like so

class Value(val foo: String, val bar: String) {
  def isTooLong: Boolean = foo.length > 2
}

class StackOverflowSpec extends WordSpec with MustMatchers {
  "Result" when {
    "Right" should {
      "have property" in {
        val result: Either[Seq[Error], Seq[Value]] = Right(Seq(new Value("a", "b"), new Value("ccc", "ddd")))
        result match {
          case Left(seq) => fail
          case Right(seq) => seq.exists(_.isTooLong) must be(true)
        }
      }
    }
  }
}