Refactoring docgen to make it more unit testable.

pkg/docgen/lib/docgen.dart

 // Copyright (c) 2013, 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.
 
 /**
  * **docgen** is a tool for creating machine readable representations of Dart 
  * code metadata, including: classes, members, comments and annotations.
  * 
  * docgen is run on a `.dart` file or a directory containing `.dart` files. 
  * 
@@ skipping 57 matching lines @@
   /// State for whether imported SDK libraries should also be outputted.
   bool includeSdk;
   /// State for whether all SDK libraries should be outputted. 
   bool parseSdk;
 
   /**
    * Docgen constructor initializes the link resolver for markdown parsing.
    * Also initializes the command line arguments. 
    */
   Docgen(ArgResults argResults) {  
+    setCommandLineArguments(argResults);
+    
+    this.linkResolver = (name) => 
+        fixReference(name, _currentLibrary, _currentClass, _currentMember);
+    
+    getMirrorSystem(argResults.rest).then(analyzeMirrors);
+  }
+
+  void setCommandLineArguments(ArgResults argResults) {
     outputToYaml = argResults['yaml'] || argResults['output-format'] == 'yaml';
     outputToJson = argResults['json'] || argResults['output-format'] == 'json';
     if (outputToYaml && outputToJson) {
       throw new ArgumentError('Cannot have contradictory output flags.');
     }
     outputToYaml = outputToYaml || !outputToJson;
     includePrivate = argResults['include-private'];
     parseSdk = argResults['parse-sdk'];
     includeSdk = parseSdk || argResults['include-sdk'];
-    
-    this.linkResolver = (name) => 
-        fixReference(name, _currentLibrary, _currentClass, _currentMember);
-    
-    analyze(argResults.rest);
   }
   
   List<String> listLibraries(List<String> args) {
     // TODO(janicejl): At the moment, only have support to have either one file,
     // or one directory. This is because there can only be one package directory
     // since only one docgen is created per run. 
     if (args.length != 1) throw new UnsupportedError(usage);
     var libraries = new List<String>();
     var type = FileSystemEntity.typeSync(args[0]);
     
@@ skipping 21 matching lines @@
     var sdk = new List<String>();
     LIBRARIES.forEach((String name, LibraryInfo info) {
       if (info.documented) { 
         sdk.add('dart:$name');
         logger.info('Add to SDK: ${sdk.last}');
       }
     });
     return sdk;
   }
   
+  void analyzeMirrors(MirrorSystem mirrorSystem) {

[Emily Fortuna, 2013/06/26 19:16:43]

consider renaming to something like "setLibraries" or something in keeping with
what is actually happening in this function. Disregard if you disagree

+    if (mirrorSystem.libraries.values.isEmpty) {
+      throw new UnsupportedError('No Library Mirrors.');
+    } 
+    this.libraries = mirrorSystem.libraries.values;
+    documentLibraries();
+  }
+  
   /**
    * Analyzes set of libraries by getting a mirror system and triggers the 
    * documentation of the libraries. 
    */
-  void analyze(List<String> args) {
+  Future<MirrorSystem> getMirrorSystem(List<String> args) {
     var libraries = !parseSdk ? listLibraries(args) : listSdk();
     if (libraries.isEmpty) throw new StateError('No Libraries.');
     // DART_SDK should be set to the root of the SDK library. 
     var sdkRoot = Platform.environment['DART_SDK'];
     if (sdkRoot != null) {
       logger.info('Using DART_SDK to find SDK at $sdkRoot');
     } else {
       // If DART_SDK is not defined in the environment, 
       // assuming the dart executable is from the Dart SDK folder inside bin. 
       sdkRoot = path.dirname(path.dirname(new Options().executable));
       logger.info('SDK Root: ${sdkRoot}');
     }
     
-    getMirrorSystem(libraries, sdkRoot, packageRoot: packageDir)
-        .then((MirrorSystem mirrorSystem) {
-          if (mirrorSystem.libraries.values.isEmpty) {
-            throw new UnsupportedError('No Library Mirrors.');
-          } 
-          this.libraries = mirrorSystem.libraries.values;
-          documentLibraries();
-        });
+    return getMirrorSystemHelper(libraries, sdkRoot, packageRoot: packageDir);
   }
   
   /**
    * Analyzes set of libraries and provides a mirror system which can be used 
    * for static inspection of the source code.
    */
-  Future<MirrorSystem> getMirrorSystem(List<String> libraries,
+  Future<MirrorSystem> getMirrorSystemHelper(List<String> libraries,
         String libraryRoot, {String packageRoot}) {
     SourceFileProvider provider = new SourceFileProvider();
     api.DiagnosticHandler diagnosticHandler =
           new FormattingDiagnosticHandler(provider).diagnosticHandler;
     Uri libraryUri = currentDirectory.resolve(appendSlash('$libraryRoot'));
     Uri packageUri = null;
     if (packageRoot != null) {
       packageUri = currentDirectory.resolve(appendSlash('$packageRoot'));
     }
     List<Uri> librariesUri = <Uri>[];
     libraries.forEach((library) {
       librariesUri.add(currentDirectory.resolve(library));
     });
     return dart2js.analyze(librariesUri, libraryUri, packageUri,
         provider.readStringFromUri, diagnosticHandler,
         ['--preserve-comments', '--categories=Client,Server']);
   }
   
   /**
    * Creates documentation for filtered libraries.
    */
   void documentLibraries() {
-    _libraries.forEach((library) {
+    _libraries.forEach((lib) {
       // Files belonging to the SDK have a uri that begins with 'dart:'.
-      if (includeSdk || !library.uri.toString().startsWith('dart:')) {
-        _currentLibrary = library;
-        var result = new Library(library.qualifiedName, _getComment(library),
-            _getVariables(library.variables), _getMethods(library.functions),
-            _getClasses(library.classes));
-        if (outputToJson) {
-          _writeToFile(stringify(result.toMap()), '${result.name}.json');
-        } 
-        if (outputToYaml) {
-          _writeToFile(getYamlString(result.toMap()), '${result.name}.yaml');
-        }
-     }
+      if (includeSdk || !lib.uri.toString().startsWith('dart:')) {
+        var library = generateLibrary(lib);
+        outputLibrary(library);
+      }
     });
     // Outputs a text file with a list of files available after creating all 
     // the libraries. This will help the viewer know what files are available 
     // to read in. 
     _writeToFile(listDir("docs").join('\n'), 'library_list.txt');
-   }
+  }
+
+  Library generateLibrary(dart2js.Dart2JsLibraryMirror library) {
+    _currentLibrary = library;
+    var result = new Library(library.qualifiedName, _getComment(library),
+        _getVariables(library.variables), _getMethods(library.functions),
+        _getClasses(library.classes));
+    logger.fine('Generated library for ${result.name}');
+    return result;
+  }
+
+  void outputLibrary(Library result) {
+    if (outputToJson) {
+      _writeToFile(stringify(result.toMap()), '${result.name}.json');
+    } 
+    if (outputToYaml) {
+      _writeToFile(getYamlString(result.toMap()), '${result.name}.yaml');
+    }
+  }
 
   /// Saves list of libraries for Docgen object.
   void set libraries(value){
     _libraries = value;
   }
   
   /**
    * Returns any documentation comments associated with a mirror with
    * simple markdown converted to html.
    */
@@ skipping 292 matching lines @@
   if (!dir.existsSync()) {
     dir.createSync();
   }
   File file = new File('docs/$filename');
   if (!file.existsSync()) {
     file.createSync();
   }
   file.openSync();
   file.writeAsString(text);
 }