add a class to read and parse libraries.dart file

compiler/javatests/com/google/dart/compiler/SystemLibrariesReaderTest.java

+// Copyright (c) 2012, 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.
+package com.google.dart.compiler;
+
+import junit.framework.TestCase;
+
+import java.io.File;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Map;
+import java.util.Map.Entry;
+
+/**
+ * Test the {@link SystemLibrariesReader}
+ */
+public class SystemLibrariesReaderTest extends TestCase {
+
+  
+  public void testLibrariesFileExists(){
+    File sdkLibPath = new File(PackageLibraryManager.DEFAULT_SDK_PATH, "lib");
+    File librariesFile = new File(new File(sdkLibPath, SystemLibrariesReader.INTERNAL_DIR), SystemLibrariesReader.LIBRARIES_FILE);
+    assertTrue(librariesFile.exists());
+  }
+  
+  public void testLibrariesFileContent(){
+   File sdkLibPath = new File(PackageLibraryManager.DEFAULT_SDK_PATH, "lib");
+   URI base = sdkLibPath.toURI();
+   SystemLibrariesReader reader = new SystemLibrariesReader(sdkLibPath);
+   Map<String, Map<String, String>> librariesMap = reader.getLibrariesMap();
+   assertTrue(!librariesMap.isEmpty());
+   for (Entry<String, Map<String, String>> entry : librariesMap.entrySet()){
+     String path = entry.getValue().get("path");
+     File file;
+     try {
+       file = new File(base.resolve(new URI(null, null, path, null, null)).normalize());
+     } catch (URISyntaxException e) {
+       continue;

[danrubel, 2012/08/28 00:25:45]

Seems like we should fail if it cannot be resolved

[keertip, 2012/08/28 20:41:57]

Done.

+     }
+       assertTrue(file.exists());
+     }
+   }
+  

[danrubel, 2012/08/28 00:25:45]

Perhaps some tests to sanity check other aspects important to editor such as
platform and category.

[keertip, 2012/08/28 20:41:57]

Done.

+}