Reorganize tests for samples so the test is discoverable from the sample

samples/tests/samples/lib/observable/observable_value_tests.dart

Index: samples/tests/samples/lib/observable/observable_value_tests.dart
diff --git a/samples/tests/samples/lib/observable/observable_value_tests.dart b/samples/tests/samples/lib/observable/observable_value_tests.dart
deleted file mode 100644
index fbeeb46137e28642afaa40b9037a5d50dd066b5a..0000000000000000000000000000000000000000
--- a/samples/tests/samples/lib/observable/observable_value_tests.dart
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (c) 2011, 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.
-
-part of observable_tests;
-
-testObservableValue() {
-  test('ObservableValue', () {
-    final value = new ObservableValue<String>('initial');
-    expect(value.value, equals('initial'));
-
-    // Set value.
-    value.value = 'new';
-    expect(value.value, equals('new'));
-
-    // Change event is sent when value is changed.
-    EventSummary result = null;
-    value.addChangeListener((summary) {
-      expect(result, isNull);
-      result = summary;
-      expect(result, isNotNull);
-    });
-
-    value.value = 'newer';
-
-    expect(result, isNotNull);
-    expect(result.events.length, equals(1));
-    validateUpdate(result.events[0], value, 'value', null, 'newer', 'new');
-  });
-
-  test('does not raise event if unchanged', () {
-    final value = new ObservableValue<String>('foo');
-    expect(value.value, equals('foo'));
-
-    bool called = false;
-    value.addChangeListener((summary) { called = true; });
-
-    // Set it to the same value.
-    value.value = 'foo';
-
-    // Should not have gotten an event.
-    expect(called, isFalse);
-  });
-}