Implement missing functions on ListBase.

tests/corelib/string_codeunits_test.dart

Index: tests/corelib/string_codeunits_test.dart
diff --git a/tests/corelib/string_codeunits_test.dart b/tests/corelib/string_codeunits_test.dart
index 6e3a282a3ae20b12d11c780f3917a967a7d78dc4..ac6eb97c5cf0efa8cb9899f913573f679bd112fc 100644
--- a/tests/corelib/string_codeunits_test.dart
+++ b/tests/corelib/string_codeunits_test.dart
@@ -25,8 +25,36 @@ main() {
     // .map
     Expect.listEquals(expectedUnits.map((x) => x.toRadixString(16)).toList(),
                       units.map((x) => x.toRadixString(16)).toList());
+
+    if (s == "") {
+      Expect.throws(() => units.first, (e) => e is StateError);
+      Expect.throws(() => units.last, (e) => e is StateError);
+      Expect.throws(() => units[0], (e) => e is RangeError);
+      Expect.throws(() => units[0] = 499, (e) => e is UnsupportedError);
+      Expect.listEquals([], units.getRange(0, 0));
+      Expect.equals(-1, units.indexOf(42));
+      Expect.equals(-1, units.lastIndexOf(499));
+    } else {
+      Expect.equals(s.codeUnitAt(0), units.first);
+      Expect.equals(s.codeUnitAt(s.length - 1), units.last);
+      Expect.equals(s.codeUnitAt(0), units[0]);
+      Expect.throws(() { units[0] = 499; }, (e) => e is UnsupportedError);
+      List<int> sub = units.getRange(1, units.length - 1);
+      Expect.listEquals(s.substring(1, s.length).codeUnits, sub);
+      Expect.equals(-1, units.indexOf(-1));
+      Expect.equals(0, units.indexOf(units[0]));
+      Expect.equals(-1, units.lastIndexOf(-1));
+      Expect.equals(units.length - 1, units.lastIndexOf(units[units.length - 1]));
+    }
+
+    Iterable reversed = units.reversed;
+    int i = units.length - 1;
+    for (int codeUnit in reversed) {
+      Expect.equals(units[i--], codeUnit);
+    }
   }
 
+  test("");
   test("abc");
   test("\x00\u0000\u{000000}");
   test("\u{ffff}\u{10000}\u{10ffff}");