Add a ScheduledStream class and some stream matchers.

pkg/scheduled_test/lib/src/utils.dart

Index: pkg/scheduled_test/lib/src/utils.dart
diff --git a/pkg/scheduled_test/lib/src/utils.dart b/pkg/scheduled_test/lib/src/utils.dart
index 9cba0447190a1b440d4f9af8dd721abad11f1229..cdecefb3ec8771b2f5c0a4bf131a4b638131c7d3 100644
--- a/pkg/scheduled_test/lib/src/utils.dart
+++ b/pkg/scheduled_test/lib/src/utils.dart
@@ -25,6 +25,52 @@ class Pair<E, F> {
   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) {
@@ -231,12 +277,5 @@ bool fullMatch(String string, Pattern pattern) {
 /// 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();
 }