Experiment using the Eff monad to test deeply nested structures

eff-match-result.scala

val e = Option(List(Right(2), Left("bad")))

runResult {
  for {
    as <- (e must beSome).opt
    a  <- fromList(as)
    i  <- (a must beRight).opt
    _  <- (i must be_>(0)).check
  } yield ()
}

// without eff
e must beSome { ss: List[Either[String, Int]] =>
  ss must contain { s: Either[String, Int] =>
    s must beRight { i: Int =>
      i must be_>(0)
    }
  }.forall
}

output

// with eff this prints
[error]  Context
[error]    Some(List(Right(2), Left(bad))): OK
[error]    Right(2): OK
[error]    2: OK
[error]    'Left(bad)' is not Right (MatchEffects.scala:29)

// without eff this prints
[error]  'Some(List(Right(2), Left(bad)))' is Some but There is 1 failure
[error]  'Left(bad)' is not Right (MatchEffects.scala:38)