Migrating a block of dart 1 tests to dart 2

tests/language_strong/closure_shared_state_test.dart

-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import "package:expect/expect.dart";
-
-// Tests for closures sharing mutable bindings.
-
-var f;
-var g;
-
-setupPlain() {
-  int j = 1000;
-  // Two closures sharing variable 'j'; j initially is 1000.
-  f = (int x) {
-    var q = j;
-    j = x;
-    return q;
-  };
-  g = (int x) {
-    var q = j;
-    j = x;
-    return q;
-  };
-}
-
-setupLoop() {
-  for (int i = 0; i < 2; i++) {
-    int j = i * 1000; // The last stored closure has j initially 1000.
-    // Two closures sharing variable 'j'.
-    f = (int x) {
-      var q = j;
-      j = x;
-      return q;
-    };
-    g = (int x) {
-      var q = j;
-      j = x;
-      return q;
-    };
-  }
-}
-
-setupNestedLoop() {
-  for (int outer = 0; outer < 2; outer++) {
-    int j = outer * 1000;
-    for (int i = 0; i < 2; i++) {
-      // Two closures sharing variable 'j' in a loop at different nesting.
-      f = (int x) {
-        var q = j;
-        j = x;
-        return q;
-      };
-      g = (int x) {
-        var q = j;
-        j = x;
-        return q;
-      };
-    }
-  }
-}
-
-test(setup) {
-  setup();
-  Expect.equals(1000, f(100));
-  Expect.equals(100, f(200));
-  Expect.equals(200, f(300));
-  Expect.equals(300, g(400));
-  Expect.equals(400, g(500));
-}
-
-main() {
-  test(setupPlain);
-  test(setupLoop);
-  test(setupNestedLoop);
-}