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/SetTest.kt

@@ -0,0 +1,72 @@
+namespace test.collections
+
+import std.io.*
+import std.util.*
+import std.test.*
+import java.util.*
+
+class SetTest() : TestSupport() {
+  val data = hashSet("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)
+
+    // TODO ideally foo would now be a set
+    todo {
+      assert("Filter on a Set should return a Set") {
+        foo is Set<String>
+      }
+    }
+  }
+
+  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 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)
+  }
+
+}