Factor out flutter manifest logic (#12237)

packages/flutter_tools/lib/src/asset.dart

@@ -5,7 +5,6 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:json_schema/json_schema.dart';
 import 'package:yaml/yaml.dart';
 
 import 'base/file_system.dart';
@@ -13,6 +12,7 @@ import 'build_info.dart';
 import 'cache.dart';
 import 'dart/package_map.dart';
 import 'devfs.dart';
+import 'flutter_manifest.dart';
 import 'globals.dart';
 
 /// A bundle of assets.
@@ -72,27 +72,16 @@ class AssetBundle {
   }) async {
     workingDirPath ??= getAssetBuildDirectory();
     packagesPath ??= fs.path.absolute(PackageMap.globalPackagesPath);
-    Object manifest;
+    FlutterManifest flutterManifest;
     try {
-      manifest = _loadFlutterManifest(manifestPath);
+      flutterManifest = await FlutterManifest.createFromPath(manifestPath);
+      if (flutterManifest == null)
+        return 1;
     } catch (e) {
       printStatus('Error detected in pubspec.yaml:', emphasis: true);
       printError('$e');
       return 1;
     }
-    if (manifest == null) {
-      // No manifest file found for this application.
-      entries[_kAssetManifestJson] = new DevFSStringContent('{}');
-      return 0;
-    }
-    if (manifest != null) {
-      final int result = await _validateFlutterManifest(manifest);
-      if (result != 0)
-        return result;
-    }
-    Map<String, dynamic> manifestDescriptor = manifest;
-    final String appName = manifestDescriptor['name'];
-    manifestDescriptor = manifestDescriptor['flutter'] ?? <String, dynamic>{};
     final String assetBasePath = fs.path.dirname(fs.path.absolute(manifestPath));
 
     _lastBuildTimestamp = new DateTime.now();
@@ -105,7 +94,7 @@ class AssetBundle {
     // see _AssetDirectoryCache.
     final Map<_Asset, List<_Asset>> assetVariants = _parseAssets(
       packageMap,
-      manifestDescriptor,
+      flutterManifest,
       assetBasePath,
       excludeDirs: <String>[workingDirPath, getBuildDirectory()]
     );
@@ -113,47 +102,42 @@ class AssetBundle {
     if (assetVariants == null)
       return 1;
 
-    final bool usesMaterialDesign = (manifestDescriptor != null) &&
-        manifestDescriptor.containsKey('uses-material-design') &&
-        manifestDescriptor['uses-material-design'];
+    final List<Map<String, dynamic>> fonts = _parseFonts(
+      flutterManifest,
+      includeDefaultFonts,
+      packageMap,
+    );
 
-    // Add assets from packages.
-    final List<Map<String, dynamic>> fonts = <Map<String, dynamic>>[];
+    // Add fonts and assets from packages.
     for (String packageName in packageMap.map.keys) {
       final Uri package = packageMap.map[packageName];
       if (package != null && package.scheme == 'file') {
         final String packageManifestPath = package.resolve('../pubspec.yaml').path;
-        final Object packageManifest = _loadFlutterManifest(packageManifestPath);
-        if (packageManifest == null)
+        final FlutterManifest packageFlutterManifest = await FlutterManifest.createFromPath(packageManifestPath);
+        if (packageFlutterManifest == null)
           continue;
-        final int result = await _validateFlutterManifest(packageManifest);
-        if (result == 0) {
-          Map<String, dynamic> packageManifestDescriptor = packageManifest;
-          // Skip the app itself.
-          if (packageManifestDescriptor['name'] == appName)
-            continue;
-          if (packageManifestDescriptor.containsKey('flutter')) {
-            packageManifestDescriptor = packageManifestDescriptor['flutter'];
-            final String packageBasePath = fs.path.dirname(packageManifestPath);
-            assetVariants.addAll(_parseAssets(
-              packageMap,
-              packageManifestDescriptor,
-              packageBasePath,
-              packageName: packageName,
-            ));
-
-            final bool packageUsesMaterialDesign =
-                packageManifestDescriptor.containsKey('uses-material-design') &&
-                packageManifestDescriptor['uses-material-design'];
-            fonts.addAll(_parseFonts(
-              packageManifestDescriptor,
-              packageUsesMaterialDesign,
-              includeDefaultFonts,
-              packageMap,
-              packageName: packageName,
-            ));
-          }
-        }
+        // Skip the app itself
+        if (packageFlutterManifest.appName == flutterManifest.appName)
+          continue;
+        final String packageBasePath = fs.path.dirname(packageManifestPath);
+
+        final Map<_Asset, List<_Asset>> packageAssets = _parseAssets(
+          packageMap,
+          packageFlutterManifest,
+          packageBasePath,
+          packageName: packageName,
+        );
+
+        if (packageAssets == null)
+          return 1;
+        assetVariants.addAll(packageAssets);
+
+        fonts.addAll(_parseFonts(
+          packageFlutterManifest,
+          includeDefaultFonts,
+          packageMap,
+          packageName: packageName,
+        ));
       }
     }
 
@@ -182,7 +166,7 @@ class AssetBundle {
     }
 
     final List<_Asset> materialAssets = <_Asset>[];
-    if (usesMaterialDesign && includeDefaultFonts) {
+    if (flutterManifest.usesMaterialDesign && includeDefaultFonts) {
       materialAssets.addAll(_getMaterialAssets(_kFontSetMaterial));
     }
     for (_Asset asset in materialAssets) {
@@ -192,12 +176,6 @@ class AssetBundle {
 
     entries[_kAssetManifestJson] = _createAssetManifest(assetVariants);
 
-    fonts.addAll(_parseFonts(
-      manifestDescriptor,
-      usesMaterialDesign,
-      includeDefaultFonts,
-      packageMap,
-    ));
 
     if (fonts.isNotEmpty)
       entries[_kFontManifestJson] = new DevFSStringContent(JSON.encode(fonts));
@@ -386,72 +364,61 @@ DevFSContent _createAssetManifest(Map<_Asset, List<_Asset>> assetVariants) {
 }
 
 List<Map<String, dynamic>> _parseFonts(
-  Map<String, dynamic> manifestDescriptor,
-  bool usesMaterialDesign,
+  FlutterManifest manifest,
   bool includeDefaultFonts,
   PackageMap packageMap, {
   String packageName
 }) {
   final List<Map<String, dynamic>> fonts = <Map<String, dynamic>>[];
-  if (usesMaterialDesign && includeDefaultFonts) {
+  if (manifest.usesMaterialDesign && includeDefaultFonts) {
     fonts.addAll(_getMaterialFonts(AssetBundle._kFontSetMaterial));
   }
-  if (manifestDescriptor != null && manifestDescriptor.containsKey('fonts'))
-    if (packageName == null) {
-      fonts.addAll(manifestDescriptor['fonts']);
-    } else {
-      fonts.addAll(_parsePackageFonts(
-        manifestDescriptor['fonts'],
-        packageName,
-        packageMap,
-      ));
-    }
+  if (packageName == null) {
+    fonts.addAll(manifest.fontsDescriptor);
+  } else {
+    fonts.addAll(_createFontsDescriptor(_parsePackageFonts(
+      manifest,
+      packageName,
+      packageMap,
+    )));
+  }
   return fonts;
 }
 
 /// Prefixes family names and asset paths of fonts included from packages with
-/// 'packages/<package_name>
-///
-/// (e.g., replace {"fonts":[{"asset":"a/bar"}],"family":"bar"} by
-/// {"fonts":[{"asset":"packages/foo/a/bar"}],"family":"packages/foo/bar"})
-List<Map<String, dynamic>> _parsePackageFonts(
-  List<Map<String, dynamic>> manifestDescriptor,
+/// 'packages/<package_name>'
+List<Font> _parsePackageFonts(
+  FlutterManifest manifest,
   String packageName,
   PackageMap packageMap,
 ) {
-  final List<Map<String, dynamic>> parsedFonts = <Map<String, dynamic>>[];
-  for (Map<String, dynamic> fontFamily in manifestDescriptor) {
-    final Map<String, dynamic> parsedFontFamily = <String, dynamic>{};
-    for (String key in fontFamily.keys) {
-      if (key == 'family') {
-        parsedFontFamily[key] = 'packages/$packageName/${fontFamily[key]}';
+  final List<Font> packageFonts = <Font>[];
+  for (Font font in manifest.fonts) {
+    final List<FontAsset> packageFontAssets = <FontAsset>[];
+    for (FontAsset fontAsset in font.fontAssets) {
+      final String assetPath = fontAsset.asset;
+      if (assetPath.startsWith('packages') &&
+          !fs.isFileSync(packageMap.map[packageName].resolve('../$assetPath').path)) {
+        packageFontAssets.add(new FontAsset(
+          fontAsset.asset,
+          weight: fontAsset.weight,
+          style: fontAsset.style,
+        ));
       } else {
-        assert(key == 'fonts');
-        final List<Map<String, dynamic>> parsedAssets = <Map<String, dynamic>>[];
-        for (Map<String, dynamic> assetProperties in fontFamily[key]) {
-          final Map<String, dynamic> parsedAssetProperties = <String, dynamic>{};
-          for (String property in assetProperties.keys) {
-            if (property == 'asset') {
-              final String assetPath = assetProperties[property];
-              if (assetPath.startsWith('packages') &&
-                  !fs.isFileSync(packageMap.map[packageName].resolve('../$assetPath').path))
-                parsedAssetProperties[property] = assetProperties[property];
-              else
-                parsedAssetProperties[property] = 'packages/$packageName/${assetProperties[property]}';
-            } else {
-              assert(property == 'style' || property == 'weight');
-              parsedAssetProperties[property] = assetProperties[property];
-            }
-          }
-          parsedAssets.add(parsedAssetProperties);
-        }
-        parsedFontFamily[key] = parsedAssets;
+        packageFontAssets.add(new FontAsset(
+          'packages/$packageName/${fontAsset.asset}',
+          weight: fontAsset.weight,
+          style: fontAsset.style,
+        ));
       }
     }
-    parsedFonts.add(parsedFontFamily);
+    packageFonts.add(new Font('packages/$packageName/${font.familyName}', packageFontAssets));
   }
+  return packageFonts;
+}
 
-  return parsedFonts;
+List<Map<String, dynamic>> _createFontsDescriptor(List<Font> fonts) {
+  return fonts.map((Font font) => font.descriptor).toList();
 }
 
 // Given an assets directory like this:
@@ -504,63 +471,48 @@ class _AssetDirectoryCache {
 /// Returns null on missing assets.
 Map<_Asset, List<_Asset>> _parseAssets(
   PackageMap packageMap,
-  Map<String, dynamic> manifestDescriptor,
+  FlutterManifest flutterManifest,
   String assetBase, {
   List<String> excludeDirs: const <String>[],
   String packageName
 }) {
   final Map<_Asset, List<_Asset>> result = <_Asset, List<_Asset>>{};
 
-  if (manifestDescriptor == null)
-    return result;
+  final _AssetDirectoryCache cache = new _AssetDirectoryCache(excludeDirs);
+  for (String assetName in flutterManifest.assets) {
+    final _Asset asset = _resolveAsset(
+      packageMap,
+      assetBase,
+      assetName,
+      packageName,
+    );
+    final List<_Asset> variants = <_Asset>[];
+    for (String path in cache.variantsFor(asset.assetFile.path)) {
+      final String key = fs.path.relative(path, from: asset.base);
+      String assetEntry;
+      if (asset.symbolicPrefix != null)
+        assetEntry = fs.path.join(asset.symbolicPrefix, key);
+      variants.add(new _Asset(base: asset.base, assetEntry: assetEntry, relativePath: key));
+    }
 
-  if (manifestDescriptor.containsKey('assets')) {
-    final _AssetDirectoryCache cache = new _AssetDirectoryCache(excludeDirs);
-    for (String assetName in manifestDescriptor['assets']) {
-      final _Asset asset = _resolveAsset(
+    result[asset] = variants;
+  }
+
+  // Add assets referenced in the fonts section of the manifest.
+  for (Font font in flutterManifest.fonts) {
+    for (FontAsset fontAsset in font.fontAssets) {
+      final _Asset baseAsset = _resolveAsset(
         packageMap,
         assetBase,
-        assetName,
+        fontAsset.asset,
         packageName,
       );
-      final List<_Asset> variants = <_Asset>[];
-      for (String path in cache.variantsFor(asset.assetFile.path)) {
-        final String key = fs.path.relative(path, from: asset.base);
-        String assetEntry;
-        if (asset.symbolicPrefix != null)
-          assetEntry = fs.path.join(asset.symbolicPrefix, key);
-        variants.add(new _Asset(base: asset.base, assetEntry: assetEntry, relativePath: key));
+      if (!baseAsset.assetFileExists) {
+        printError('Error: unable to locate asset entry in pubspec.yaml: "${fontAsset.asset}".');
+        return null;
       }
 
-      result[asset] = variants;
-    }
-  }
-
-  // Add assets referenced in the fonts section of the manifest.
-  if (manifestDescriptor.containsKey('fonts')) {
-    for (Map<String, dynamic> family in manifestDescriptor['fonts']) {
-      final List<Map<String, dynamic>> fonts = family['fonts'];
-      if (fonts == null)
-        continue;
-
-      for (Map<String, dynamic> font in fonts) {
-        final String asset = font['asset'];
-        if (asset == null)
-          continue;
-
-        final _Asset baseAsset = _resolveAsset(
-          packageMap,
-          assetBase,
-          asset,
-          packageName,
-        );
-        if (!baseAsset.assetFileExists) {
-          printError('Error: unable to locate asset entry in pubspec.yaml: "$asset".');
-          return null;
-        }
-
-        result[baseAsset] = <_Asset>[];
-      }
+      result[baseAsset] = <_Asset>[];
     }
   }
 
@@ -613,25 +565,3 @@ _Asset _resolvePackageAsset(String asset, PackageMap packageMap) {
   printError('Could not resolve package $packageKey for asset $asset.\n');
   return null;
 }
-
-dynamic _loadFlutterManifest(String manifestPath) {
-  if (manifestPath == null || !fs.isFileSync(manifestPath))
-    return null;
-  final String manifestDescriptor = fs.file(manifestPath).readAsStringSync();
-  return loadYaml(manifestDescriptor);
-}
-
-Future<int> _validateFlutterManifest(Object manifest) async {
-  final String schemaPath = fs.path.join(fs.path.absolute(Cache.flutterRoot),
-      'packages', 'flutter_tools', 'schema', 'pubspec_yaml.json');
-  final Schema schema = await Schema.createSchemaFromUrl(fs.path.toUri(schemaPath).toString());
-
-  final Validator validator = new Validator(schema);
-  if (validator.validate(manifest)) {
-    return 0;
-  } else {
-    printStatus('Error detected in pubspec.yaml:', emphasis: true);
-    printError(validator.errors.join('\n'));
-    return 1;
-  }
-}

packages/flutter_tools/lib/src/flutter_manifest.dart

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:flutter_tools/src/globals.dart';
+import 'package:json_schema/json_schema.dart';
+import 'package:yaml/yaml.dart';
+
+import 'base/file_system.dart';
+import 'cache.dart';
+
+/// A wrapper around the `flutter` section in the  `pubspec.yaml` file.
+class FlutterManifest {
+  FlutterManifest._();
+
+  /// Returns null on missing or invalid manifest
+  static Future<FlutterManifest> createFromPath(String path) async {
+    return  _createFromYaml(await _loadFlutterManifest(path));
+  }
+  /// Returns null on missing or invalid manifest
+  static Future<FlutterManifest> createFromString(String manifest) async {
+    return _createFromYaml(loadYaml(manifest));
+  }
+
+  static Future<FlutterManifest> _createFromYaml(Object yamlDocument) async {
+    final FlutterManifest pubspec = new FlutterManifest._();
+    if (yamlDocument == null || !await _validate(yamlDocument))
+      return null;
+
+    pubspec._descriptor = yamlDocument;
+    pubspec._flutterDescriptor = pubspec._descriptor['flutter'] ?? <String, dynamic>{};
+    return pubspec;
+  }
+
+  /// A map representation of the entire `pubspec.yaml` file.
+  Map<String, dynamic> _descriptor;
+
+  /// A map representation of the `flutter` section in the `pubspec.yaml` file.
+  Map<String, dynamic> _flutterDescriptor;
+
+  String get appName => _descriptor['name'];
+
+  bool get usesMaterialDesign {
+    return _flutterDescriptor['uses-material-design'] ?? false;
+  }
+
+  List<Map<String, dynamic>> get fontsDescriptor {
+   return _flutterDescriptor['fonts'] ?? const <Map<String, dynamic>>[];
+  }
+
+  List<String> get assets {
+    return _flutterDescriptor['assets'] ?? const <String>[];
+  }
+
+  List<Font> _fonts;
+
+  List<Font> get fonts {
+    _fonts ??= _extractFonts();
+    return _fonts;
+  }
+
+  List<Font> _extractFonts() {
+    if (!_flutterDescriptor.containsKey('fonts'))
+      return <Font>[];
+
+    final List<Font> fonts = <Font>[];
+    for (Map<String, dynamic> fontFamily in _flutterDescriptor['fonts']) {
+      final List<Map<String, dynamic>> fontFiles = fontFamily['fonts'];
+      final String familyName = fontFamily['family'];
+      if (familyName == null) {
+        printError('Warning: Missing family name for font.', emphasis: true);
+        continue;
+      }
+      if (fontFiles == null) {
+        printError('Warning: No fonts specified for font $familyName', emphasis: true);
+        continue;
+      }
+
+      final List<FontAsset> fontAssets = <FontAsset>[];
+      for (Map<String, dynamic> fontFile in fontFiles) {
+        final String asset = fontFile['asset'];
+        if (asset == null) {
+          printError('Warning: Missing asset in fonts for $familyName', emphasis: true);
+          continue;
+        }
+
+        fontAssets.add(new FontAsset(
+          asset,
+          weight: fontFile['weight'],
+          style: fontFile['style'],
+        ));
+      }
+      if (fontAssets.isNotEmpty)
+        fonts.add(new Font(fontFamily['family'], fontAssets));
+    }
+    return fonts;
+  }
+}
+
+class Font {
+  Font(this.familyName, this.fontAssets) {
+    assert(familyName != null);
+    assert(fontAssets != null);
+    assert(fontAssets.isNotEmpty);
+  }
+
+  final String familyName;
+  final List<FontAsset> fontAssets;
+
+  Map<String, dynamic> get descriptor {
+    return <String, dynamic>{
+      'family': familyName,
+      'fonts': fontAssets.map((FontAsset a) => a.descriptor).toList(),
+    };
+  }
+
+  @override
+  String toString() => '$runtimeType(family: $familyName, assets: $fontAssets)';
+}
+
+class FontAsset {
+  FontAsset(this.asset, {this.weight, this.style}) {
+    assert(asset != null);
+  }
+
+  final String asset;
+  final int weight;
+  final String style;
+
+  Map<String, dynamic> get descriptor {
+    final Map<String, dynamic> descriptor = <String, dynamic>{};
+    if (weight != null)
+      descriptor['weight'] = weight;
+
+    if (style != null)
+      descriptor['style'] = style;
+
+    descriptor['asset'] = asset;
+    return descriptor;
+  }
+
+  @override
+  String toString() => '$runtimeType(asset: $asset, weight; $weight, style: $style)';
+}
+
+Future<dynamic> _loadFlutterManifest(String manifestPath) async {
+  if (manifestPath == null || !fs.isFileSync(manifestPath))
+    return null;
+  final String manifestDescriptor = await fs.file(manifestPath).readAsString();
+  return loadYaml(manifestDescriptor);
+}
+
+Future<bool> _validate(Object manifest) async {
+  final String schemaPath = fs.path.join(
+    fs.path.absolute(Cache.flutterRoot), 'packages', 'flutter_tools', 'schema',
+    'pubspec_yaml.json',
+  );
+  final Schema schema = await Schema.createSchemaFromUrl(fs.path.toUri(schemaPath).toString());
+
+  final Validator validator = new Validator(schema);
+  if (validator.validate(manifest)) {
+    return true;
+  } else {
+    printStatus('Error detected in pubspec.yaml:', emphasis: true);
+    printError(validator.errors.join('\n'));
+    return false;
+  }
+}
\ No newline at end of file

packages/flutter_tools/test/asset_bundle_package_fonts_test.dart

@@ -180,8 +180,8 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -211,8 +211,8 @@ $fontsSection
       writeFontAsset('p2/p/lib/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package2/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package2/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -243,8 +243,8 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"weight":400,"style":"italic","asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"}]';
+          '[{"family":"packages/test_package/foo",'
+          '"fonts":[{"weight":400,"style":"italic","asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[],
         <String>[font],
@@ -278,9 +278,9 @@ $fontsSection
       writeFontAsset('p/p/', font);
 
       final String expectedFontManifest =
-          '[{"fonts":[{"asset":"packages/test_package/a/bar"}],'
-          '"family":"packages/test_package/foo"},'
-          '{"fonts":[{"asset":"a/bar"}],"family":"foo"}]';
+          '[{"fonts":[{"asset":"a/bar"}],"family":"foo"},'
+          '{"family":"packages/test_package/foo",'
+          '"fonts":[{"asset":"packages/test_package/a/bar"}]}]';
       await buildAndVerifyFonts(
         <String>[font],
         <String>[font],

packages/flutter_tools/test/flutter_manifest_test.dart

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/flutter_manifest.dart';
+
+import 'package:test/test.dart';
+
+import 'src/common.dart';
+import 'src/context.dart';
+
+void main() {
+  setUpAll(() {
+    Cache.flutterRoot = getFlutterRoot();
+  });
+
+  group('FlutterManifest', () {
+    test('has no fonts or assets when the "flutter" section is empty', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+      expect(flutterManifest, isNotNull);
+      expect(flutterManifest.appName, 'test');
+      expect(flutterManifest.usesMaterialDesign, false);
+      expect(flutterManifest.fontsDescriptor, isEmpty);
+      expect(flutterManifest.fonts, isEmpty);
+      expect(flutterManifest.assets, isEmpty);
+    });
+
+    test('knows if material design is used', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+      expect(flutterManifest.usesMaterialDesign, true);
+    });
+
+    test('has two assets', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  assets:
+    - a/foo
+    - a/bar
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+      expect(flutterManifest.assets, <String>['a/foo', 'a/bar']);
+    });
+
+    test('has one font family with one asset', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      expect(flutterManifest.fontsDescriptor.toString(), '[{fonts: [{asset: a/bar}], family: foo}]');
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 1);
+      final Font font = fonts[0];
+      final String fontDescriptor = '{family: foo, fonts: [{asset: a/bar}]}';
+      expect(font.descriptor.toString(), fontDescriptor);
+      expect(font.familyName, 'foo');
+      final List<FontAsset> assets = font.fontAssets;
+      expect(assets.length, 1);
+      final FontAsset fontAsset = assets[0];
+      expect(fontAsset.asset, 'a/bar');
+      expect(fontAsset.weight, isNull);
+      expect(fontAsset.style, isNull);
+    });
+
+    test('has one font family with a simple asset and one with weight', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+        - asset: a/bar
+          weight: 400
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      final String expectedFontsDescriptor = '[{fonts: [{asset: a/bar}, {weight: 400, asset: a/bar}], family: foo}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 1);
+      final Font font = fonts[0];
+      final String fontDescriptor = '{family: foo, fonts: [{asset: a/bar}, {weight: 400, asset: a/bar}]}';
+      expect(font.descriptor.toString(), fontDescriptor);
+      expect(font.familyName, 'foo');
+      final List<FontAsset> assets = font.fontAssets;
+      expect(assets.length, 2);
+      final FontAsset fontAsset0 = assets[0];
+      expect(fontAsset0.asset, 'a/bar');
+      expect(fontAsset0.weight, isNull);
+      expect(fontAsset0.style, isNull);
+      final FontAsset fontAsset1 = assets[1];
+      expect(fontAsset1.asset, 'a/bar');
+      expect(fontAsset1.weight, 400);
+      expect(fontAsset1.style, isNull);
+    });
+
+    test('has one font family with a simple asset and one with weight and style', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+        - asset: a/bar
+          weight: 400
+          style: italic
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      final String expectedFontsDescriptor = '[{fonts: [{asset: a/bar}, {style: italic, weight: 400, asset: a/bar}], family: foo}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 1);
+      final Font font = fonts[0];
+      final String fontDescriptor = '{family: foo, fonts: [{asset: a/bar}, {weight: 400, style: italic, asset: a/bar}]}';
+      expect(font.descriptor.toString(), fontDescriptor);
+      expect(font.familyName, 'foo');
+      final List<FontAsset> assets = font.fontAssets;
+      expect(assets.length, 2);
+      final FontAsset fontAsset0 = assets[0];
+      expect(fontAsset0.asset, 'a/bar');
+      expect(fontAsset0.weight, isNull);
+      expect(fontAsset0.style, isNull);
+      final FontAsset fontAsset1 = assets[1];
+      expect(fontAsset1.asset, 'a/bar');
+      expect(fontAsset1.weight, 400);
+      expect(fontAsset1.style, 'italic');
+    });
+
+    test('has two font families, each with one simple asset and one with weight and style', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+        - asset: a/bar
+          weight: 400
+          style: italic
+    - family: bar
+      fonts:
+        - asset: a/baz
+        - weight: 400
+          asset: a/baz
+          style: italic
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      final String expectedFontsDescriptor = '[{fonts: [{asset: a/bar}, {style: italic, weight: 400, asset: a/bar}], family: foo},'
+                                             ' {fonts: [{asset: a/baz}, {style: italic, weight: 400, asset: a/baz}], family: bar}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 2);
+
+      final Font fooFont = fonts[0];
+      final String barFontDescriptor = '{family: foo, fonts: [{asset: a/bar}, {weight: 400, style: italic, asset: a/bar}]}';
+      expect(fooFont.descriptor.toString(), barFontDescriptor);
+      expect(fooFont.familyName, 'foo');
+      final List<FontAsset> fooAassets = fooFont.fontAssets;
+      expect(fooAassets.length, 2);
+      final FontAsset fooFontAsset0 = fooAassets[0];
+      expect(fooFontAsset0.asset, 'a/bar');
+      expect(fooFontAsset0.weight, isNull);
+      expect(fooFontAsset0.style, isNull);
+      final FontAsset fooFontAsset1 = fooAassets[1];
+      expect(fooFontAsset1.asset, 'a/bar');
+      expect(fooFontAsset1.weight, 400);
+      expect(fooFontAsset1.style, 'italic');
+
+      final Font barFont = fonts[1];
+      final String fontDescriptor = '{family: bar, fonts: [{asset: a/baz}, {weight: 400, style: italic, asset: a/baz}]}';
+      expect(barFont.descriptor.toString(), fontDescriptor);
+      expect(barFont.familyName, 'bar');
+      final List<FontAsset> barAssets = barFont.fontAssets;
+      expect(barAssets.length, 2);
+      final FontAsset barFontAsset0 = barAssets[0];
+      expect(barFontAsset0.asset, 'a/baz');
+      expect(barFontAsset0.weight, isNull);
+      expect(barFontAsset0.style, isNull);
+      final FontAsset barFontAsset1 = barAssets[1];
+      expect(barFontAsset1.asset, 'a/baz');
+      expect(barFontAsset1.weight, 400);
+      expect(barFontAsset1.style, 'italic');
+    });
+
+    testUsingContext('has only one of two font familes when one declaration is missing the "family" option', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+        - asset: a/bar
+          weight: 400
+          style: italic
+    - fonts:
+        - asset: a/baz
+        - asset: a/baz
+          weight: 400
+          style: italic
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+
+      final String expectedFontsDescriptor = '[{fonts: [{asset: a/bar}, {style: italic, weight: 400, asset: a/bar}], family: foo},'
+                                             ' {fonts: [{asset: a/baz}, {style: italic, weight: 400, asset: a/baz}]}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 1);
+      final Font fooFont = fonts[0];
+      final String barFontDescriptor = '{family: foo, fonts: [{asset: a/bar}, {weight: 400, style: italic, asset: a/bar}]}';
+      expect(fooFont.descriptor.toString(), barFontDescriptor);
+      expect(fooFont.familyName, 'foo');
+      final List<FontAsset> fooAassets = fooFont.fontAssets;
+      expect(fooAassets.length, 2);
+      final FontAsset fooFontAsset0 = fooAassets[0];
+      expect(fooFontAsset0.asset, 'a/bar');
+      expect(fooFontAsset0.weight, isNull);
+      expect(fooFontAsset0.style, isNull);
+      final FontAsset fooFontAsset1 = fooAassets[1];
+      expect(fooFontAsset1.asset, 'a/bar');
+      expect(fooFontAsset1.weight, 400);
+      expect(fooFontAsset1.style, 'italic');
+    });
+
+    testUsingContext('has only one of two font familes when one declaration is missing the "fonts" option', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - asset: a/bar
+        - asset: a/bar
+          weight: 400
+          style: italic
+    - family: bar
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      final String expectedFontsDescriptor = '[{fonts: [{asset: a/bar}, {style: italic, weight: 400, asset: a/bar}], family: foo},'
+                                             ' {family: bar}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 1);
+      final Font fooFont = fonts[0];
+      final String barFontDescriptor = '{family: foo, fonts: [{asset: a/bar}, {weight: 400, style: italic, asset: a/bar}]}';
+      expect(fooFont.descriptor.toString(), barFontDescriptor);
+      expect(fooFont.familyName, 'foo');
+      final List<FontAsset> fooAassets = fooFont.fontAssets;
+      expect(fooAassets.length, 2);
+      final FontAsset fooFontAsset0 = fooAassets[0];
+      expect(fooFontAsset0.asset, 'a/bar');
+      expect(fooFontAsset0.weight, isNull);
+      expect(fooFontAsset0.style, isNull);
+      final FontAsset fooFontAsset1 = fooAassets[1];
+      expect(fooFontAsset1.asset, 'a/bar');
+      expect(fooFontAsset1.weight, 400);
+      expect(fooFontAsset1.style, 'italic');
+    });
+
+    testUsingContext('has no font family when declaration is missing the "asset" option', () async {
+      final String manifest = '''
+name: test
+dependencies:
+  flutter:
+    sdk: flutter
+flutter:
+  uses-material-design: true
+  fonts:
+    - family: foo
+      fonts:
+        - weight: 400
+''';
+      final FlutterManifest flutterManifest = await FlutterManifest.createFromString(manifest);
+
+      final String expectedFontsDescriptor = '[{fonts: [{weight: 400}], family: foo}]';
+      expect(flutterManifest.fontsDescriptor.toString(), expectedFontsDescriptor);
+      final List<Font> fonts = flutterManifest.fonts;
+      expect(fonts.length, 0);
+    });
+  });
+}