Bug fix for highlighting that drifts

editor/tools/plugins/com.google.dart.tools.ui_test/src/com/google/dart/tools/ui/internal/text/functions/BufferedDocumentScannerTest.java

Index: editor/tools/plugins/com.google.dart.tools.ui_test/src/com/google/dart/tools/ui/internal/text/functions/BufferedDocumentScannerTest.java
===================================================================
--- editor/tools/plugins/com.google.dart.tools.ui_test/src/com/google/dart/tools/ui/internal/text/functions/BufferedDocumentScannerTest.java	(revision 0)
+++ editor/tools/plugins/com.google.dart.tools.ui_test/src/com/google/dart/tools/ui/internal/text/functions/BufferedDocumentScannerTest.java	(revision 0)
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2011, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * 
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.dart.tools.ui.internal.text.functions;
+
+import junit.framework.TestCase;
+
+import org.eclipse.jface.text.Document;
+
+public class BufferedDocumentScannerTest extends TestCase {
+  public void test_BufferedDocumentScanner_peek() {
+    BufferedDocumentScanner scanner = new BufferedDocumentScanner(10);
+    String content = "1234567890abcdefghijklmnopqrstuvwxyz";
+    int length = content.length();
+    scanner.setRange(new Document(content), 0, length);
+    for (int i = 0; i < length; i++) {
+      assertEquals("Wrong value at " + i, content.charAt(i), scanner.peek(0));
+      scanner.read();
+    }
+  }
+
+  public void test_BufferedDocumentScanner_peek_crossBuffer() {
+    int bufferLength = 10;
+    int halfOffset = 3;
+    BufferedDocumentScanner scanner = new BufferedDocumentScanner(bufferLength);
+    String content = "1234567890abcdefghijklmnopqrstuvwxyz";
+    int length = content.length();
+    scanner.setRange(new Document(content), 0, length);
+    for (int i = 0; i < bufferLength - halfOffset; i++) {
+      scanner.read();
+    }
+    assertEquals("Wrong value at " + (bufferLength + halfOffset),
+        content.charAt(bufferLength + halfOffset), scanner.peek(halfOffset + halfOffset));
+  }
+}