Add some basic interfaces that will be used for the test runner.

lib/src/state.dart

+// Copyright (c) 2015, 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 unittest.state;
+
+/// The state of a [LiveTest].
+///
+/// A test's state is made up of two components, its [status] and its [result].
+/// The [status] represents where the test is in its process of running; the
+/// [result] represents the outcome as far as its known.
+class State {
+  /// Where the test is in its process of running.
+  final Status status;
+
+  /// The outcome of the test, as far as it's known.
+  ///
+  /// Note that if [status] is [Status.pending], [result] will always be
+  /// [Result.success] since the test hasn't yet had a chance to fail.
+  final Result result;
+
+  const State(this.status, this.result);
+
+  bool operator==(other) => other is State && status == other.status &&
+      result == other.result;
+
+  int get hashCode => status.hashCode ^ (7 * result.hashCode);
+
+  String toString() {
+    if (status == Status.pending) return "pending";
+    if (status == Status.complete) return result.toString();
+    if (result == Result.success) return "running";
+    return "running with $result";
+  }
+}
+
+/// Where the test is in its process of running.
+class Status {
+  /// The test has not yet begun running.
+  static const pending = const Status._("pending");
+
+  /// The test is currently running.
+  static const running = const Status._("running");
+
+  /// The test has finished running.
+  ///
+  /// Note that even if the test is marked [complete], it may still be running
+  /// code asynchronously. A test is considered complete either once it hits its
+  /// first error or when all [expectAsync] callbacks have been called and any
+  /// returned [Future] has completed, but it's possible for further processing
+  /// to happen, which may cause further errors.
+  static const complete = const Status._("complete");
+
+  /// The name of the status.
+  final String name;
+
+  factory Status.parse(String name) {
+    switch (name) {
+      case "pending": return Status.pending;
+      case "running": return Status.running;
+      case "complete": return Status.complete;
+      default:
+        throw new ArgumentError('Invalid status name "$name".');
+    }
+  }
+
+  const Status._(this.name);
+
+  String toString() => name;
+}
+
+/// The outcome of the test, as far as it's known.
+class Result {
+  /// The test has not yet failed in any way.
+  ///
+  /// Note that this doesn't mean that the test won't fail in the future.
+  static const success = const Result._("success");
+
+  /// The test has failed.
+  ///
+  /// A failure is specifically caused by a [TestFailure] being thrown; any
+  /// other exception causes an error.
+  static const failure = const Result._("failure");
+
+  /// The test has crashed.
+  ///
+  /// Any exception other than a [TestFailure] is considered to be an error.
+  static const error = const Result._("error");
+
+  /// The name of the result.
+  final String name;
+
+  factory Result.parse(String name) {
+    switch (name) {
+      case "success": return Result.success;
+      case "failure": return Result.failure;
+      case "error": return Result.error;
+      default:
+        throw new ArgumentError('Invalid result name "$name".');
+    }
+  }
+
+  const Result._(this.name);
+
+  String toString() => name;
+}