Roll Observatory packages and add a roll script

packages/dart_style/test/source_code_test.dart

+// Copyright (c) 2014, 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 dart_style.test.source_code_test;
+
+import 'package:test/test.dart';
+
+import 'package:dart_style/dart_style.dart';
+
+void main() {
+  var selection =
+      new SourceCode("123456;", selectionStart: 3, selectionLength: 2);
+  var noSelection = new SourceCode("123456;");
+
+  group('constructor', () {
+    test('throws on negative start', () {
+      expect(() {
+        new SourceCode("12345;", selectionStart: -1, selectionLength: 0);
+      }, throwsArgumentError);
+    });
+
+    test('throws on out of bounds start', () {
+      expect(() {
+        new SourceCode("12345;", selectionStart: 7, selectionLength: 0);
+      }, throwsArgumentError);
+    });
+
+    test('throws on negative length', () {
+      expect(() {
+        new SourceCode("12345;", selectionStart: 1, selectionLength: -1);
+      }, throwsArgumentError);
+    });
+
+    test('throws on out of bounds length', () {
+      expect(() {
+        new SourceCode("12345;", selectionStart: 2, selectionLength: 5);
+      }, throwsArgumentError);
+    });
+
+    test('throws is start is null and length is not', () {
+      expect(() {
+        new SourceCode("12345;", selectionStart: 0);
+      }, throwsArgumentError);
+    });
+
+    test('throws is length is null and start is not', () {
+      expect(() {
+        new SourceCode("12345;", selectionLength: 1);
+      }, throwsArgumentError);
+    });
+  });
+
+  group('textBeforeSelection', () {
+    test('gets substring before selection', () {
+      expect(selection.textBeforeSelection, equals("123"));
+    });
+
+    test('gets entire string if no selection', () {
+      expect(noSelection.textBeforeSelection, equals("123456;"));
+    });
+  });
+
+  group('selectedText', () {
+    test('gets selection substring', () {
+      expect(selection.selectedText, equals("45"));
+    });
+
+    test('gets empty string if no selection', () {
+      expect(noSelection.selectedText, equals(""));
+    });
+  });
+
+  group('textAfterSelection', () {
+    test('gets substring after selection', () {
+      expect(selection.textAfterSelection, equals("6;"));
+    });
+
+    test('gets empty string if no selection', () {
+      expect(noSelection.textAfterSelection, equals(""));
+    });
+  });
+}