Add capture/release for results in package:async

pkg/async/test/result_test.dart

Index: pkg/async/test/result_test.dart
diff --git a/pkg/async/test/result_test.dart b/pkg/async/test/result_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..53472ec905917cd5de0ac331da93213ab7c8f10a
--- /dev/null
+++ b/pkg/async/test/result_test.dart
@@ -0,0 +1,265 @@
+// Copyright (c) 2013, 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 "dart:collection";
+import "package:async/result.dart";
+import "package:unittest/unittest.dart";
+
+void main() {
+  StackTrace stack;
+  try { throw 0; } catch (e, s) { stack = s; }
+
+  test("create result value", () {
+    Result<int> result = new Result<int>.value(42);
+    expect(result.isValue, isTrue);
+    expect(result.isError, isFalse);
+    ValueResult value = result.asValue;
+    expect(value.value, equals(42));
+  });
+
+  test("create result value 2", () {
+    Result<int> result = new ValueResult<int>(42);
+    expect(result.isValue, isTrue);
+    expect(result.isError, isFalse);
+    ValueResult<int> value = result.asValue;
+    expect(value.value, equals(42));
+  });
+
+  test("create result error", () {
+    Result<bool> result = new Result<bool>.error("BAD", stack);
+    expect(result.isValue, isFalse);
+    expect(result.isError, isTrue);
+    ErrorResult error = result.asError;
+    expect(error.error, equals("BAD"));
+    expect(error.stackTrace, same(stack));
+  });
+
+  test("create result error 2", () {
+    Result<bool> result = new ErrorResult<bool>("BAD", stack);
+    expect(result.isValue, isFalse);
+    expect(result.isError, isTrue);
+    ErrorResult error = result.asError;
+    expect(error.error, equals("BAD"));
+    expect(error.stackTrace, same(stack));
+  });
+
+  test("create result error no stack", () {
+    Result<bool> result = new Result<bool>.error("BAD");
+    expect(result.isValue, isFalse);
+    expect(result.isError, isTrue);
+    ErrorResult error = result.asError;
+    expect(error.error, equals("BAD"));
+    expect(error.stackTrace, isNull);
+  });
+
+  test("complete with value", () {
+    Result<int> result = new ValueResult<int>(42);
+    Completer c = new Completer<int>();
+    c.future.then(expectAsync((int v) { expect(v, equals(42)); }),
+                  onError: (e, s) { fail("Unexpected error"); });
+    result.complete(c);
+  });
+
+  test("complete with error", () {
+    Result<bool> result = new ErrorResult("BAD", stack);
+    Completer c = new Completer<bool>();
+    c.future.then((bool v) { Expect.fail("Unexpected value $v"); },
+                  onError: expectAsync((e, s) {
+                    expect(e, equals("BAD"));
+                    expect(s, same(stack));
+                  }));
+    result.complete(c);
+  });
+
+  test("add sink value", () {
+    Result<int> result = new ValueResult<int>(42);
+    EventSink<int> sink = new TestSink(
+        onData: expectAsync((v) { expect(v, equals(42)); })
+    );
+    result.addTo(sink);
+  });
+
+  test("add sink error", () {
+    Result<bool> result = new ErrorResult("BAD", stack);
+    EventSink<bool> sink = new TestSink(
+        onError: expectAsync((e, s) {
+          expect(e, equals("BAD"));
+          expect(s, same(stack));
+        })
+    );
+    result.addTo(sink);
+  });
+
+  test("value as future", () {
+    Result<int> result = new ValueResult<int>(42);
+    result.asFuture.then(expectAsync((int v) { expect(v, equals(42)); }),
+                         onError: (e, s) { fail("Unexpected error"); });
+  });
+
+  test("error as future", () {
+    Result<bool> result = new ErrorResult("BAD", stack);
+    result.asFuture.then((bool v) { Expect.fail("Unexpected value $v"); },
+                         onError: expectAsync((e, s) {
+                           expect(e, equals("BAD"));
+                           expect(s, same(stack));
+                         }));
+  });
+
+  test("capture future value", () {
+    Future<int> value = new Future<int>.value(42);
+    Result.capture(value).then(expectAsync((Result result) {
+      expect(result.isValue, isTrue);
+      expect(result.isError, isFalse);
+      ValueResult value = result.asValue;
+      expect(value.value, equals(42));
+    }), onError: (e, s) {
+      Expect.fail("Unexpected error: $e");
+    });
+  });
+
+  test("capture future error", () {
+    Future<bool> value = new Future<bool>.error("BAD", stack);
+    Result.capture(value).then(expectAsync((Result result) {
+      expect(result.isValue, isFalse);
+      expect(result.isError, isTrue);
+      ErrorResult error = result.asError;
+      expect(error.error, equals("BAD"));
+      expect(error.stackTrace, same(stack));
+    }), onError: (e, s) {
+      Expect.fail("Unexpected error: $e");
+    });
+  });
+
+  test("release future value", () {
+    Future<Result<int>> future =
+        new Future<Result<int>>.value(new Result<int>.value(42));
+    Result.release(future).then(expectAsync((v) {
+      expect(v, equals(42));
+    }), onError: (e, s) {
+      Expect.fail("Unexpected error: $e");
+    });
+  });
+
+  test("release future error", () {
+    // An error in the result is unwrapped and reified by release.
+    Future<Result<bool>> future =
+        new Future<Result<bool>>.value(new Result<bool>.error("BAD", stack));
+    Result.release(future).then((v) {
+      Expect.fail("Unexpected value: $v");
+    }, onError: expectAsync((e, s) {
+      expect(e, equals("BAD"));
+      expect(s, same(stack));
+    }));
+  });
+
+  test("release future real error", () {
+    // An error in the error lane is passed through by release.
+    Future<Result<bool>> future = new Future<Result<bool>>.error("BAD", stack);
+    Result.release(future).then((v) {
+      Expect.fail("Unexpected value: $v");
+    }, onError: expectAsync((e, s) {
+      expect(e, equals("BAD"));
+      expect(s, same(stack));
+    }));
+  });
+
+  test("capture stream", () {
+    StreamController<int> c = new StreamController<int>();
+    Stream<Result> stream = Result.captureStream(c.stream);
+    var expectedList = new Queue.from([new Result.value(42),
+                                       new Result.error("BAD", stack),
+                                       new Result.value(37)]);
+    void listener(Result actual) {
+      expect(expectedList.isEmpty, isFalse);
+      expectResult(actual, expectedList.removeFirst());
+    }
+    stream.listen(expectAsync(listener, count: 3),
+                  onError: (e, s) { fail("Unexpected error: $e"); },
+                  onDone: expectAsync((){}),
+                  cancelOnError: true);
+    c.add(42);
+    c.addError("BAD", stack);
+    c.add(37);
+    c.close();
+  });
+
+  test("release stream", () {
+    StreamController<Result<int>> c = new StreamController<Result<int>>();
+    Stream<int> stream = Result.releaseStream(c.stream);
+    List events = [new Result<int>.value(42),
+                   new Result<int>.error("BAD", stack),
+                   new Result<int>.value(37)];
+    // Expect the data events, and an extra error event.
+    var expectedList = new Queue.from(events)..add(new Result.error("BAD2"));
+    void dataListener(int v) {
+      expect(expectedList.isEmpty, isFalse);
+      Result expected = expectedList.removeFirst();
+      expect(expected.isValue, isTrue);
+      expect(v, equals(expected.asValue.value));
+    }
+    void errorListener(error, StackTrace stackTrace) {
+      expect(expectedList.isEmpty, isFalse);
+      Result expected = expectedList.removeFirst();
+      expect(expected.isError, isTrue);
+      expect(error, equals(expected.asError.error));
+      expect(stackTrace, same(expected.asError.stackTrace));
+    }
+    stream.listen(expectAsync(dataListener, count: 2),
+                  onError: expectAsync(errorListener, count: 2),
+                  onDone: expectAsync((){}));
+    for (Result<int> result in events) {
+      c.add(result);  // Result value or error in data line.
+    }
+    c.addError("BAD2");  // Error in error line.
+    c.close();
+  });
+
+  test("release stream cancel on error", () {
+    StreamController<Result<int>> c = new StreamController<Result<int>>();
+    Stream<int> stream = Result.releaseStream(c.stream);
+    stream.listen(expectAsync((v) { expect(v, equals(42)); }),
+                  onError: expectAsync((e, s) {
+                    expect(e, equals("BAD"));
+                    expect(s, same(stack));
+                  }),
+                  onDone: () { fail("Unexpected done event"); },
+                  cancelOnError: true);
+    c.add(new Result.value(42));
+    c.add(new Result.error("BAD", stack));
+    c.add(new Result.value(37));
+    c.close();
+  });
+}
+
+void expectResult(Result actual, Result expected) {
+  expect(actual.isValue, equals(expected.isValue));
+  expect(actual.isError, equals(expected.isError));
+  if (actual.isValue) {
+    expect(actual.asValue.value, equals(expected.asValue.value));
+  } else {
+    expect(actual.asError.error, equals(expected.asError.error));
+    expect(actual.asError.stackTrace, same(expected.asError.stackTrace));
+  }
+}
+
+class TestSink<T> implements EventSink<T> {
+  final Function onData;
+  final Function onError;
+  final Function onDone;
+
+  TestSink({void this.onData(T data) : _nullData,
+            void this.onError(e, StackTrace s) : _nullError,
+            void this.onDone() : _nullDone });
+
+  void add(T value) { onData(value); }
+  void addError(error, [StackTrace stack]) { onError(error, stack); }
+  void close() { onDone(); }
+
+  static void _nullData(value) { Expect.fail("Unexpected sink add: $value"); }
+  static void _nullError(e, StackTrace s) {
+    Expect.fail("Unexpected sink addError: $e");
+  }
+  static void _nullDone() { Expect.fail("Unepxected sink close"); }
+}