first cut of the collection methods in the standard library in http://confluence.jetbrains.net/display/JET/Standard+Library along with a little testlib to test them. Still a few TODO things and tidy up (and am sure a few more methods could be very handy too) but its getting Kool :)

testlib/test/CollectionTest.kt

@@ -0,0 +1,123 @@
+namespace test.collections
+
+import std.test.*
+
+// TODO can we avoid importing all this stuff by default I wonder?
+// e.g. making println and the collection builder methods public by default?
+import std.io.*
+import std.util.*
+import java.util.*
+
+class CollectionTest() : TestSupport() {
+  val data = arrayList("foo", "bar")
+
+  fun testAny() {
+    assert {
+      data.any{it.startsWith("f")}
+    }
+    assertNot {
+      data.any{it.startsWith("x")}
+    }
+  }
+
+  fun testAll() {
+    assert {
+      data.all{it.length == 3}
+    }
+    assertNot {
+      data.all{s => s.startsWith("b")}
+    }
+  }
+
+  fun testFilter() {
+    val foo = data.filter{it.startsWith("f")}
+
+    assert {
+      foo.all{it.startsWith("f")}
+    }
+    assertEquals(1, foo.size)
+    assertEquals(arrayList("foo"), foo)
+  }
+
+  fun testFind() {
+    val x = data.find{it.startsWith("x")}
+    assertNull(x)
+    fails {
+      x.sure()
+    }
+
+    val f = data.find{it.startsWith("f")}
+    f.sure()
+    assertEquals("foo", f)
+  }
+
+  fun testFlatMap() {
+    /**
+      TODO compiler bug
+      we should be able to remove the explicit type on the function
+      http://youtrack.jetbrains.net/issue/KT-849
+    */
+    // TODO there should be a neater way to do this :)
+
+    val characters = arrayList('f', 'o', 'o', 'b', 'a', 'r')
+    /*
+    val characters = data.flatMap<String,Character>{
+      Arrays.asList((it as java.lang.String).toCharArray()) as Collection<Character>
+    }
+    */
+    todo {
+      println("Got list of characters ${characters}")
+      val text = characters.join("")
+      assertEquals("foobar", text)
+    }
+  }
+
+  fun testForeach() {
+    var count = 0
+    val x = data.foreach{ count += it.length }
+    assertEquals(6, count)
+  }
+
+  fun testJoin() {
+    val text = data.join("-", "<", ">")
+    assertEquals("<foo-bar>", text)
+  }
+
+  fun testMap() {
+    /**
+      TODO compiler bug
+      we should be able to remove the explicit type on the function
+      http://youtrack.jetbrains.net/issue/KT-849
+    */
+    val lengths = data.map<String,Int>{s => s.length}
+    assert {
+      lengths.all{it == 3}
+    }
+    assertEquals(2, lengths.size)
+    assertEquals(arrayList(3, 3), lengths)
+  }
+
+  fun testSort() {
+    val coll: List<String> = arrayList("foo", "bar", "abc")
+
+    // TODO fixme
+    // Some sort of in/out variance thing - or an issue with Java interop?
+    //coll.sort()
+    todo {
+      assertEquals(3, coll.size)
+      assertEquals(arrayList("abc", "bar", "foo"), coll)
+
+    }
+  }
+
+  fun testToArray() {
+    val arr = data.toArray()
+    println("Got array ${arr}")
+    todo {
+      assert {
+        arr is Array<String>
+      }
+    }
+  }
+
+}