// Some iterator grouped/sliding unit tests
object Test {
def it = (1 to 10).iterator
def assertThat[T](expectedLength: Int, expectedLast: Seq[T])(it: Iterator[Seq[T]]): Unit = {
val xs = it.toList
def fail(msg: String) = "assertion failed on %s: %s".format(xs, msg)
assert(xs.size == expectedLength, fail("expected length " + expectedLength))
assert(xs.last == expectedLast, fail("expected last " + expectedLast))
}
def main(args: Array[String]): Unit = {
val itSum = it.toStream.sum
for (i <- it) {
// sum of the groups == sum of the original
val thisSum = ((it grouped i) map (_.sum)).toStream.sum
assert(thisSum == itSum, thisSum + " != " + itSum)
}
// grouped
assertThat(4, List(10)) { it grouped 3 }
assertThat(3, List(7, 8, 9)) { it grouped 3 withPartial false }
assertThat(4, List(10, -1, -1)) { it grouped 3 withPadding -1 }
// testing by-name padding
val padIt = it
assertThat(4, List(10, 1, 2)) { it grouped 3 withPadding padIt.next }
// sliding
assertThat(8, List(8, 9, 10)) { it sliding 3 }
assertThat(3, (3 to 10).toList) { it sliding 8 }
assertThat(2, List(9, 10)) { it.sliding(8, 8) }
assertThat(1, (1 to 8).toList) { it.sliding(8, 8) withPartial false }
assertThat(2, List(9, 10, -1, -1, -1)) { it.sliding(5, 8) withPadding -1 }
assertThat(1, (1 to 5).toList) { it.sliding(5, 8) withPartial false }
// larger step than window
assertThat(5, List(9)) { it.sliding(1, 2) }
assertThat(3, List(9, 10)) { it.sliding(2, 4) }
// make sure it throws past the end
val thrown = try {
val it = List(1,2,3).sliding(2)
it.next
it.next
it.next
false
}
catch {
case _: NoSuchElementException => true
}
assert(thrown)
}
}