diff options
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/src/main/scala/tests.scala | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/tests/src/main/scala/tests.scala b/tests/src/main/scala/tests.scala index 4b0e5c1..bc33969 100644 --- a/tests/src/main/scala/tests.scala +++ b/tests/src/main/scala/tests.scala @@ -47,6 +47,14 @@ object Test { def apply(a: String, b: String): Test = Test(Param(a, b)) } +sealed trait Politician[+S] +case class Accountable[+S](slogan: S) extends Politician[S] +case class Corrupt[+S, +L <: Seq[Company]](slogan: S, lobby: L) extends Politician[S] + +sealed trait Box[+A] +case class SimpleBox[+A](value: A) extends Box[A] +case class LabelledBox[+A, L <: String](value: A, var label: L) extends Box[A] + object Tests extends TestApp { def tests() = for (i <- 1 to 1000) { @@ -201,5 +209,20 @@ object Tests extends TestApp { test("serialize a value class") { Show.gen[Length].show(new Length(100)) }.assert(_ == "100") + + // Corrupt being covariant in L <: Seq[Company] enables the derivation for Corrupt[String, _] + test("show a Politician with covariant lobby") { + Show.gen[Politician[String]].show(Corrupt("wall", Seq(Company("Alice Inc")))) + }.assert(_ == "Corrupt(slogan=wall,lobby=[Company(name=Alice Inc)])") + + // LabelledBox being invariant in L <: String prohibits the derivation for LabelledBox[Int, _] + test("can't show a Box with invariant label") { + scalac"Show.gen[Box[Int]]" + }.assert { _ == TypecheckError( + txt"""magnolia: could not find typeclass for type L + | in parameter 'label' of product type magnolia.tests.LabelledBox[Int, _ <: String] + | in coproduct type magnolia.tests.Box[Int] + |""") + } } } |