Make pub generate .packages file.

test/descriptor/packages.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.
+
+/// Pub-specific scheduled_test descriptors.
+library descriptor.packages_file;
+
+import "dart:io" show File;
+import "dart:async" show Future;
+import "dart:convert" show UTF8;
+
+import 'package:package_config/packages_file.dart' as packages_file;
+import 'package:path/path.dart' as p;
+import 'package:scheduled_test/descriptor.dart';
+import 'package:scheduled_test/scheduled_test.dart';
+
+import '../test_pub.dart';
+
+/// Describes a `.packages` file and its contents.
+class PackagesFileDescriptor extends Descriptor {
+  // RegExp recognizing semantic version numbers.
+  static final _semverRE =
+      new RegExp(r"^(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*)"
+                r"(?:-[a-zA-Z\d-]+)?(?:\+[a-zA-Z\d-]+)?$");
+
+  final _dependencies;
+
+  /// Describes a `.packages` file with the given dependencies.
+  ///
+  /// Dependencies maps package name to semantic version.
+  PackagesFileDescriptor([Map<String, String> dependencies])
+      : _dependencies = dependencies,
+        super('.packages');
+
+  Future create([String parent]) => schedule(() {
+    if (parent == null) parent = defaultRoot;
+    var contents = const <int>[];
+    if (_dependencies != null) {
+      var mapping = {};
+      _dependencies.forEach((package, version) {
+        var packagePath;
+        if (_semverRE.hasMatch(version)) {
+          // If it's a semver, it's a cache reference.
+          packagePath = p.join(cachePath, "$package-$version");
+        } else {
+          // Otherwise it's a path relative to the .pubspec file,
+          // which is also the relative path wrt. the .packages file.
+          packagePath = version;
+        }
+        mapping[package] = p.toUri(p.join(packagePath, "lib", ""));
+      });
+      var buffer = new StringBuffer();
+      packages_file.write(buffer, mapping);
+      contents = UTF8.encode(buffer.toString());
+    }
+    return new File(p.join(parent, name)).writeAsBytes(contents);
+  }, "creating file '$name'");
+
+  Future validate([String parent]) =>
+    schedule(() => validateNow(parent), "validating file '$name'");
+
+  Future validateNow([String parent]) {
+    // Copied from FileDescriptor in scheduled_test.
+    if (parent == null) parent = defaultRoot;
+    var fullPath = p.join(parent, name);
+    if (!new File(fullPath).existsSync()) {
+      fail("File not found: '$fullPath'.");
+    }
+    return new File(fullPath).readAsBytes()
+        .then((bytes) => _validateNow(bytes, fullPath));
+  }
+
+  /// A function that throws an error if [binaryContents] doesn't match the
+  /// expected contents of the descriptor.
+  void _validateNow(List<int> binaryContents, String fullPath) {
+    var fileUri = p.toUri(fullPath);
+    var map = packages_file.parse(binaryContents, fileUri);
+
+    for (var package in _dependencies.keys) {
+      if (!map.containsKey(package)) {
+        fail(".packages does not contain $package entry");
+      }
+      var version = _dependencies[package];
+      if (_semverRE.hasMatch(version)) {
+        if (!map[package].path.contains(version)) {
+          fail(".packages of $package has incorrect version. "
+               "Expected $version, found location: ${map[package]}.");
+        }
+      } else {
+        var packagePath = fileUri.resolve("$version/lib/");
+        if (!packagePath.path.endsWith('/')) {
+          packagePath = packagePath.replace(path: packagePath.path + '/');
+        }
+        if ("${map[package]}" != "$packagePath") {
+          fail("Relative path: Expected $packagePath, found ${map[package]}");
+        }
+      }
+    }
+
+    if (map.length != _dependencies.length) {
+      for (var key in map.keys) {
+        if (!_dependencies.containsKey(key)) {
+          fail(".packages file contains unexpected entry: $key");
+        }
+      }
+    }
+  }
+
+  String describe() => name;
+}