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package scala
import org.junit.Test
import org.junit.Assert._
import org.junit.runner.RunWith
import org.junit.runners.JUnit4
import scala.tools.testing.AssertUtil._
@RunWith(classOf[JUnit4])
class BoxUnboxTest {
def genericNull[T] = null.asInstanceOf[T] // allowed, see SI-4437, point 2
@Test
def boxUnboxInt(): Unit = {
val b = new Integer(1)
val u = 1
assertEquals(1.toInt, u)
assertEquals(Predef.int2Integer(1), b)
assertEquals(1: Integer, b)
assertEquals(Int.box(1), b)
assertEquals(1.asInstanceOf[Object], b)
assertThrows[ClassCastException]("".asInstanceOf[Integer])
assertEquals(Predef.Integer2int(b), u)
assertEquals(b: Int, u)
assertEquals(Int.unbox(b), u)
assertEquals(b.asInstanceOf[Int], u)
assertEquals(b.intValue, u)
assertEquals(b.toInt, u)
intWrapper(b).toInt
assertThrows[ClassCastException](Int.unbox(""))
assertThrows[ClassCastException]("".asInstanceOf[Int])
// null unboxing in various positions
val n1 = Int.unbox(null)
assertEquals(n1, 0)
val n2 = Predef.Integer2int(null)
assertEquals(n2, 0)
val n3 = (null: Integer): Int
assertEquals(n3, 0)
val n4 = null.asInstanceOf[Int]
assertEquals(n4, 0)
val n5 = null.asInstanceOf[Int] == 0
assertTrue(n5)
val n6 = null.asInstanceOf[Int] == null
assertFalse(n6)
val n7 = null.asInstanceOf[Int] != 0
assertFalse(n7)
val n8 = null.asInstanceOf[Int] != null
assertTrue(n8)
val mp = new java.util.HashMap[Int, Int]
val n9 = mp.get(0)
assertEquals(n9, 0)
val n10 = mp.get(0) == null // SI-602
assertThrows[AssertionError](assertFalse(n10)) // should not throw
def f(a: Any) = "" + a
val n11 = f(null.asInstanceOf[Int])
assertEquals(n11, "0")
def n12 = genericNull[Int]
assertEquals(n12, 0)
}
@Test
def numericConversions(): Unit = {
val i1 = 1L.asInstanceOf[Int]
assertEquals(i1, 1)
assertThrows[ClassCastException] {
val i2 = (1L: Any).asInstanceOf[Int] // SI-1448, should not throw. see also SI-4437 point 1.
assertEquals(i2, 1)
}
}
@Test
def boxUnboxBoolean(): Unit = {
val n1 = Option(null.asInstanceOf[Boolean])
assertEquals(n1, Some(false))
}
@Test
def boxUnboxUnit(): Unit = {
// should not use assertEquals in this test: it takes two Object parameters. normally, Unit does
// not conform to Object, but for Java-defined methods scalac makes an exception and treats them
// as Any. passing a Unit as Any makes the compiler go through another layer of boxing, so it
// can hide some bugs (where we actually have a null, but the compiler makes it a ()).
var v = 0
def eff() = { v = 1 }
def chk() = { assert(v == 1); v = 0 }
val b = runtime.BoxedUnit.UNIT
assert(eff() == b); chk()
assert(Unit.box(eff()) == b); chk()
assert(().asInstanceOf[Object] == b)
Unit.unbox({eff(); b}); chk()
Unit.unbox({eff(); null}); chk()
assertThrows[ClassCastException](Unit.unbox({eff(); ""})); chk()
val n1 = null.asInstanceOf[Unit]
assert(n1 == b)
val n2 = null.asInstanceOf[Unit] == b
assert(n2)
def f(a: Any) = "" + a
val n3 = f(null.asInstanceOf[Unit])
assertEquals(n3, "()")
}
}
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