The fruit of a bunch of iteration on Iterator.

Flexible yet simple/clean API for grouped and sliding.

1 files changed, 37 insertions, 0 deletions

diff --git a/test/files/run/unittest_iterator.scala b/test/files/run/unittest_iterator.scala
new file mode 100644
index 0000000000..93aaa4a834
--- /dev/null
+++ b/test/files/run/unittest_iterator.scala
@@ -0,0 +1,37 @@
+// 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]]) {
+    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 }
+  }
+}