Add a ScheduledStream class and some stream matchers.

pkg/scheduled_test/lib/src/utils.dart

 // 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.
 
 library utils;
 
 import 'dart:async';
 
 import 'package:stack_trace/stack_trace.dart';
 
 /// A pair of values.
 class Pair<E, F> {
   E first;
   F last;
 
   Pair(this.first, this.last);
 
   String toString() => '($first, $last)';
 
   bool operator==(other) {
     if (other is! Pair) return false;
     return other.first == first && other.last == last;
   }
 
   int get hashCode => first.hashCode ^ last.hashCode;
 }
 
+/// A class that represents one and only one of two types of values.
+class Either<E, F> {
+  /// Whether this is a value of type `E`.
+  final bool isFirst;
+
+  /// Whether this is a value of type `F`.
+  bool get isSecond => !isFirst;
+
+  /// The value, either of type `E` or `F`.
+  final _value;
+
+  /// The value of type `E`.
+  ///
+  /// It's an error to access this is this is of type `F`.

[Bob Nystrom, 2013/12/21 00:11:34]

"this is this" -> "this if the value"

[nweiz, 2014/01/07 03:16:39]

N/A

+  E get first {
+    assert(isFirst);
+    return _value;
+  }
+
+  /// The value of type `F`.
+  ///
+  /// It's an error to access this is this is of type `E`.

[Bob Nystrom, 2013/12/21 00:11:34]

Ditto.

[nweiz, 2014/01/07 03:16:39]

N/A

+  F get second {
+    assert(isSecond);
+    return _value;
+  }
+
+  /// Creates an [Either] with type `E`.
+  Either.withFirst(this._value)

[Bob Nystrom, 2013/12/21 00:11:34]

Maybe just Either.first()?

[nweiz, 2014/01/07 03:16:39]

N/A

+      : isFirst = true;
+
+  /// Creates an [Either] with type `F`.
+  Either.withSecond(this._value)
+      : isFirst = false;
+
+  /// Runs [whenFirst] or [whenSecond] depending on the type of [this].
+  ///
+  /// Returns the result of whichvever function was run.
+  match(whenFirst(E value), whenSecond(F value)) {
+    if (isFirst) return whenFirst(first);
+    return whenSecond(second);
+  }
+
+  String toString() => "$_value (${isFirst? 'first' : 'second'})";
+}
+
 /// Configures [future] so that its result (success or exception) is passed on
 /// to [completer].
 void chainToCompleter(Future future, Completer completer) {
   future.then(completer.complete, onError: completer.completeError);
 }
 
 /// Like [Future.sync], but wraps the Future in [Chain.track] as well.
 Future syncFuture(callback()) => Chain.track(new Future.sync(callback));
 
 /// Prepends each line in [text] with [prefix]. If [firstPrefix] is passed, the
@@ skipping 186 matching lines @@
 /// Returns whether [pattern] matches all of [string].
 bool fullMatch(String string, Pattern pattern) {
   var matches = pattern.allMatches(string);
   if (matches.isEmpty) return false;
   return matches.first.start == 0 && matches.first.end == string.length;
 }
 
 /// Returns a string representation of [trace] that has the core and test frames
 /// folded together.
 String terseTraceString(StackTrace trace) {
-  return new Chain(new Chain.forTrace(trace).traces.map((trace) {
-    return trace.foldFrames((frame) {
-      return frame.package == 'scheduled_test' ||
-             frame.package == 'unittest' ||
-             frame.package == 'stack_trace' ||
-             frame.isCore;
-    });
-  })).terse.toString().trim();
+  return new Chain.forTrace(trace).terse.toString().trim();
 }