Add typed wrapper functions to delegate classes.

test/typed_wrapper/future_test.dart

+// Copyright (c) 2016, 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 'dart:async';
+
+import "package:async/async.dart";
+import "package:async/src/typed/future.dart";
+import "package:test/test.dart";
+
+import '../utils.dart';
+
+void main() {
+  group("with valid types, forwards", () {
+    var wrapper;
+    var errorWrapper;
+    setUp(() {
+      wrapper = new TypeSafeFuture<int>(new Future<Object>.value(12));
+
+      var error = new Future<Object>.error("oh no");
+      error.catchError((_) {}); // Don't let the error cause the test to fail.
+      errorWrapper = new TypeSafeFuture<int>(error);
+    });
+
+    test("asStream()", () {
+      expect(wrapper.asStream().toList(), completion(equals([12])));
+      expect(errorWrapper.asStream().first, throwsA("oh no"));
+    });
+
+    test("catchError()", () {
+      expect(
+          wrapper.catchError(expectAsync((_) {}, count: 0),
+              test: expectAsync((_) {}, count: 0)),
+          completion(equals(12)));
+
+      expect(errorWrapper.catchError(expectAsync((error) {
+        expect(error, equals("oh no"));
+        return "value";
+      }), test: expectAsync((error) {
+        expect(error, equals("oh no"));
+        return true;
+      })), completion(equals("value")));
+    });
+
+    test("then()", () {
+      expect(wrapper.then((value) => value.toString()),
+          completion(equals("12")));
+      expect(errorWrapper.then(expectAsync((_) {}, count: 0)),
+          throwsA("oh no"));
+    });
+
+    test("whenComplete()", () {
+      expect(wrapper.whenComplete(expectAsync(() {})), completion(equals(12)));
+      expect(errorWrapper.whenComplete(expectAsync(() {})), throwsA("oh no"));
+    });
+
+    test("timeout()", () {
+      expect(wrapper.timeout(new Duration(seconds: 1)), completion(equals(12)));
+      expect(errorWrapper.timeout(new Duration(seconds: 1)), throwsA("oh no"));
+
+      expect(
+          new TypeSafeFuture<int>(new Completer<Object>().future)
+              .timeout(Duration.ZERO),
+          throwsA(new isInstanceOf<TimeoutException>()));
+
+      expect(
+          new TypeSafeFuture<int>(new Completer<Object>().future)
+              .timeout(Duration.ZERO, onTimeout: expectAsync(() => 15)),
+          completion(equals(15)));
+    });
+  });
+
+  group("with invalid types", () {
+    var wrapper;
+    setUp(() {
+      wrapper = new TypeSafeFuture<int>(new Future<Object>.value("foo"));
+    });
+
+    group("throws a CastError for", () {
+      test("asStream()", () {
+        expect(wrapper.asStream().first, throwsCastError);
+      });
+
+      test("then()", () {
+        expect(
+            wrapper.then(expectAsync((_) {}, count: 0),
+                onError: expectAsync((_) {}, count: 0)),
+            throwsCastError);
+      });
+
+      test("whenComplete()", () {
+        expect(wrapper.whenComplete(expectAsync(() {})).then((_) {}),
+            throwsCastError);
+      });
+
+      test("timeout()", () {
+        expect(wrapper.timeout(new Duration(seconds: 3)).then((_) {}),
+            throwsCastError);
+
+      expect(
+          new TypeSafeFuture<int>(new Completer<Object>().future)
+              .timeout(Duration.ZERO, onTimeout: expectAsync(() => "foo"))
+              .then((_) {}),
+          throwsCastError);
+      });
+    });
+
+    group("doesn't throw a CastError for", () {
+      test("catchError()", () {
+        // catchError has a Future<dynamic> return type, so even if there's no
+        // error we don't re-wrap the returned future.
+        expect(wrapper.catchError(expectAsync((_) {}, count: 0)),
+            completion(equals("foo")));
+      });
+    });
+  });
+}