lib/src/runner/configuration.dart - test - Git at Google

 // Copyright (c) 2015, 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.

 import 'dart:async';

 import 'package:boolean_selector/boolean_selector.dart';
 import 'package:collection/collection.dart';
 import 'package:glob/glob.dart';
 import 'package:path/path.dart' as p;

 import '../backend/platform_selector.dart';
 import '../backend/test_platform.dart';
 import '../frontend/timeout.dart';
 import '../util/io.dart';
 import 'configuration/args.dart' as args;
 import 'configuration/load.dart';
 import 'configuration/reporters.dart';
 import 'configuration/suite.dart';
 import 'configuration/values.dart';

 /// The key used to look up [Configuration.current] in a zone.
 final _currentKey = new Object();

 /// A class that encapsulates the command-line configuration of the test runner.
 class Configuration {
   /// An empty configuration with only default values.
   ///
   /// Using this is slightly more efficient than manually constructing a new
   /// configuration with no arguments.
   static final empty = new Configuration._();

   /// The usage string for the command-line arguments.
   static String get usage => args.usage;

   /// Whether `--help` was passed.
   bool get help => _help ?? false;
   final bool _help;

   /// Whether `--version` was passed.
   bool get version => _version ?? false;
   final bool _version;

   /// Whether to pause for debugging after loading each test suite.
   bool get pauseAfterLoad => _pauseAfterLoad ?? false;
   final bool _pauseAfterLoad;

   /// The path to the file from which to load more configuration information.
   ///
   /// This is *not* resolved automatically.
   String get configurationPath => _configurationPath ?? "dart_test.yaml";
   final String _configurationPath;

   /// The path to dart2js.
   String get dart2jsPath => _dart2jsPath ?? p.join(sdkDir, 'bin', 'dart2js');
   final String _dart2jsPath;

   /// The name of the reporter to use to display results.
   String get reporter => _reporter ?? defaultReporter;
   final String _reporter;

   /// Whether to disable retries of tests.
   bool get noRetry => _noRetry ?? false;
   final bool _noRetry;

   /// The URL for the `pub serve` instance from which to load tests, or `null`
   /// if tests should be loaded from the filesystem.
   final Uri pubServeUrl;

   /// Whether to use command-line color escapes.
   bool get color => _color ?? canUseSpecialChars;
   final bool _color;

   /// How many tests to run concurrently.
   int get concurrency =>
       pauseAfterLoad ? 1 : (_concurrency ?? defaultConcurrency);
   final int _concurrency;

   /// The index of the current shard, if sharding is in use, or `null` if it's
   /// not.
   ///
   /// Sharding is a technique that allows the Google internal test framework to
   /// easily split a test run across multiple workers without requiring the
   /// tests to be modified by the user. When sharding is in use, the runner gets
   /// a shard index (this field) and a total number of shards, and is expected
   /// to provide the following guarantees:
   ///
   /// * Running the same invocation of the runner, with the same shard index and
   ///   total shards, will run the same set of tests.
   /// * Across all shards, each test must be run exactly once.
   ///
   /// In addition, tests should be balanced across shards as much as possible.
   final int shardIndex;

   /// The total number of shards, if sharding is in use, or `null` if it's not.
   ///
   /// See [shardIndex] for details.
   final int totalShards;

   /// The list of packages to fold when producing [StackTrace]s.
   Set<String> get foldTraceExcept => _foldTraceExcept ?? new Set();
   final Set<String> _foldTraceExcept;

   /// If non-empty, all packages not in this list will be folded when producing
   /// [StackTrace]s.
   Set<String> get foldTraceOnly => _foldTraceOnly ?? new Set();
   final Set<String> _foldTraceOnly;

   /// The paths from which to load tests.
   List<String> get paths => _paths ?? ["test"];
   final List<String> _paths;

   /// Whether the load paths were passed explicitly or the default was used.
   bool get explicitPaths => _paths != null;

   /// The glob matching the basename of tests to run.
   ///
   /// This is used to find tests within a directory.
   Glob get filename => _filename ?? defaultFilename;
   final Glob _filename;

   /// The set of presets to use.
   ///
   /// Any chosen presets for the parent configuration are added to the chosen
   /// preset sets for child configurations as well.
   ///
   /// Note that the order of this set matters.
   final Set<String> chosenPresets;

   /// The set of tags that have been declared in any way in this configuration.
   Set<String> get knownTags {
     if (_knownTags != null) return _knownTags;

     var known = suiteDefaults.knownTags.toSet();
     for (var configuration in presets.values) {
       known.addAll(configuration.knownTags);
     }

     _knownTags = new UnmodifiableSetView(known);
     return _knownTags;
   }

   Set<String> _knownTags;

   /// Configuration presets.
   ///
   /// These are configurations that can be explicitly selected by the user via
   /// the command line. Preset configuration takes precedence over the base
   /// configuration.
   ///
   /// This is guaranteed not to have any keys that match [chosenPresets]; those
   /// are resolved when the configuration is constructed.
   final Map<String, Configuration> presets;

   /// All preset names that are known to be valid.
   ///
   /// This includes presets that have already been resolved.
   Set<String> get knownPresets {
     if (_knownPresets != null) return _knownPresets;

     var known = presets.keys.toSet();
     for (var configuration in presets.values) {
       known.addAll(configuration.knownPresets);
     }

     _knownPresets = new UnmodifiableSetView(known);
     return _knownPresets;
   }

   Set<String> _knownPresets;

   /// The default suite-level configuration.
   final SuiteConfiguration suiteDefaults;

   /// Returns the current configuration, or a default configuration if no
   /// current configuration is set.
   ///
   /// The current configuration is set using [asCurrent].
   static Configuration get current =>
       Zone.current[_currentKey] ?? new Configuration();

   /// Parses the configuration from [args].
   ///
   /// Throws a [FormatException] if [args] are invalid.
   factory Configuration.parse(List<String> arguments) => args.parse(arguments);

   /// Loads the configuration from [path].
   ///
   /// If [global] is `true`, this restricts the configuration file to only rules
   /// that are supported globally.
   ///
   /// Throws an [IOException] if [path] does not exist or cannot be read. Throws
   /// a [FormatException] if its contents are invalid.
   factory Configuration.load(String path, {bool global: false}) =>
       load(path, global: global);

   factory Configuration(
       {bool help,
       bool version,
       bool pauseAfterLoad,
       bool color,
       String configurationPath,
       String dart2jsPath,
       String reporter,
       int pubServePort,
       int concurrency,
       int shardIndex,
       int totalShards,
       Iterable<String> paths,
       Iterable<String> foldTraceExcept,
       Iterable<String> foldTraceOnly,
       Glob filename,
       Iterable<String> chosenPresets,
       Map<String, Configuration> presets,
       bool noRetry,

       // Suite-level configuration
       bool jsTrace,
       bool runSkipped,
       Iterable<String> dart2jsArgs,
       String precompiledPath,
       Iterable<Pattern> patterns,
       Iterable<TestPlatform> platforms,
       BooleanSelector includeTags,
       BooleanSelector excludeTags,
       Map<BooleanSelector, SuiteConfiguration> tags,
       Map<PlatformSelector, SuiteConfiguration> onPlatform,

       // Test-level configuration
       Timeout timeout,
       bool verboseTrace,
       bool chainStackTraces,
       bool skip,
       int retry,
       String skipReason,
       PlatformSelector testOn,
       Iterable<String> addTags}) {
     var chosenPresetSet = chosenPresets?.toSet();
     var configuration = new Configuration._(
         help: help,
         version: version,
         pauseAfterLoad: pauseAfterLoad,
         color: color,
         configurationPath: configurationPath,
         dart2jsPath: dart2jsPath,
         reporter: reporter,
         pubServePort: pubServePort,
         concurrency: concurrency,
         shardIndex: shardIndex,
         totalShards: totalShards,
         paths: paths,
         foldTraceExcept: foldTraceExcept,
         foldTraceOnly: foldTraceOnly,
         filename: filename,
         chosenPresets: chosenPresetSet,
         presets: _withChosenPresets(presets, chosenPresetSet),
         noRetry: noRetry,
         suiteDefaults: new SuiteConfiguration(
             jsTrace: jsTrace,
             runSkipped: runSkipped,
             dart2jsArgs: dart2jsArgs,
             precompiledPath: precompiledPath,
             patterns: patterns,
             platforms: platforms,
             includeTags: includeTags,
             excludeTags: excludeTags,
             tags: tags,
             onPlatform: onPlatform,

             // Test-level configuration
             timeout: timeout,
             verboseTrace: verboseTrace,
             chainStackTraces: chainStackTraces,
             skip: skip,
             retry: retry,
             skipReason: skipReason,
             testOn: testOn,
             addTags: addTags));
     return configuration._resolvePresets();
   }

   static Map<Object, Configuration> _withChosenPresets(
       Map<Object, Configuration> map, Set<String> chosenPresets) {
     if (map == null || chosenPresets == null) return map;
     return mapMap(map,
         value: (_, config) => config.change(
             chosenPresets: config.chosenPresets.union(chosenPresets)));
   }

   /// Creates new Configuration.
   ///
   /// Unlike [new Configuration], this assumes [presets] is already resolved.
   Configuration._(
       {bool help,
       bool version,
       bool pauseAfterLoad,
       bool color,
       String configurationPath,
       String dart2jsPath,
       String reporter,
       int pubServePort,
       int concurrency,
       this.shardIndex,
       this.totalShards,
       Iterable<String> paths,
       Iterable<String> foldTraceExcept,
       Iterable<String> foldTraceOnly,
       Glob filename,
       Iterable<String> chosenPresets,
       Map<String, Configuration> presets,
       bool noRetry,
       SuiteConfiguration suiteDefaults})
       : _help = help,
         _version = version,
         _pauseAfterLoad = pauseAfterLoad,
         _color = color,
         _configurationPath = configurationPath,
         _dart2jsPath = dart2jsPath,
         _reporter = reporter,
         pubServeUrl = pubServePort == null
             ? null
             : Uri.parse("http://localhost:$pubServePort"),
         _concurrency = concurrency,
         _paths = _list(paths),
         _foldTraceExcept = _set(foldTraceExcept),
         _foldTraceOnly = _set(foldTraceOnly),
         _filename = filename,
         chosenPresets =
             new UnmodifiableSetView(chosenPresets?.toSet() ?? new Set()),
         presets = _map(presets),
         _noRetry = noRetry,
         suiteDefaults = pauseAfterLoad == true
             ? suiteDefaults?.change(timeout: Timeout.none) ??
                 new SuiteConfiguration(timeout: Timeout.none)
             : suiteDefaults ?? SuiteConfiguration.empty {
     if (_filename != null && _filename.context.style != p.style) {
       throw new ArgumentError(
           "filename's context must match the current operating system, was "
           "${_filename.context.style}.");
     }

     if ((shardIndex == null) != (totalShards == null)) {
       throw new ArgumentError(
           "shardIndex and totalShards may only be passed together.");
     } else if (shardIndex != null) {
       RangeError.checkValueInInterval(
           shardIndex, 0, totalShards - 1, "shardIndex");
     }
   }

   /// Creates a new [Configuration] that takes its configuration from
   /// [SuiteConfiguration].
   factory Configuration.fromSuiteConfiguration(
           SuiteConfiguration suiteConfig) =>
       new Configuration._(suiteDefaults: suiteConfig);

   /// Returns an unmodifiable copy of [input].
   ///
   /// If [input] is `null` or empty, this returns `null`.
   static List/*<T>*/ _list/*<T>*/(Iterable/*<T>*/ input) {
     if (input == null) return null;
     var list = new List/*<T>*/ .unmodifiable(input);
     if (list.isEmpty) return null;
     return list;
   }

   /// Returns a set from [input].
   static Set<T> _set<T>(Iterable<T> input) {
     if (input == null) return null;
     var set = new Set<T>.from(input);
     if (set.isEmpty) return null;
     return set;
   }

   /// Returns an unmodifiable copy of [input] or an empty unmodifiable map.
   static Map/*<K, V>*/ _map/*<K, V>*/(Map/*<K, V>*/ input) {
     if (input == null || input.isEmpty) return const {};
     return new Map.unmodifiable(input);
   }

   /// Runs [body] with [this] as [Configuration.current].
   ///
   /// This is zone-scoped, so [this] will be the current configuration in any
   /// asynchronous callbacks transitively created by [body].
   /*=T*/ asCurrent/*<T>*/(/*=T*/ body()) =>
       runZoned(body, zoneValues: {_currentKey: this});

   /// Merges this with [other].
   ///
   /// For most fields, if both configurations have values set, [other]'s value
   /// takes precedence. However, certain fields are merged together instead.
   /// This is indicated in those fields' documentation.
   Configuration merge(Configuration other) {
     if (this == Configuration.empty) return other;
     if (other == Configuration.empty) return this;

     var foldTraceOnly = other._foldTraceOnly ?? _foldTraceOnly;
     var foldTraceExcept = other._foldTraceExcept ?? _foldTraceExcept;
     if (_foldTraceOnly != null) {
       if (other._foldTraceExcept != null) {
         foldTraceOnly = _foldTraceOnly.difference(other._foldTraceExcept);
       } else if (other._foldTraceOnly != null) {
         foldTraceOnly = other._foldTraceOnly.intersection(_foldTraceOnly);
       }
     } else if (_foldTraceExcept != null) {
       if (other._foldTraceOnly != null) {
         foldTraceOnly = other._foldTraceOnly.difference(_foldTraceExcept);
       } else if (other._foldTraceExcept != null) {
         foldTraceExcept = other._foldTraceExcept.union(_foldTraceExcept);
       }
     }

     var result = new Configuration._(
         help: other._help ?? _help,
         version: other._version ?? _version,
         pauseAfterLoad: other._pauseAfterLoad ?? _pauseAfterLoad,
         color: other._color ?? _color,
         configurationPath: other._configurationPath ?? _configurationPath,
         dart2jsPath: other._dart2jsPath ?? _dart2jsPath,
         reporter: other._reporter ?? _reporter,
         pubServePort: (other.pubServeUrl ?? pubServeUrl)?.port,
         concurrency: other._concurrency ?? _concurrency,
         shardIndex: other.shardIndex ?? shardIndex,
         totalShards: other.totalShards ?? totalShards,
         paths: other._paths ?? _paths,
         foldTraceExcept: foldTraceExcept,
         foldTraceOnly: foldTraceOnly,
         filename: other._filename ?? _filename,
         chosenPresets: chosenPresets.union(other.chosenPresets),
         presets: _mergeConfigMaps(presets, other.presets),
         noRetry: other._noRetry ?? _noRetry,
         suiteDefaults: suiteDefaults.merge(other.suiteDefaults));
     result = result._resolvePresets();

     // Make sure the merged config preserves any presets that were chosen and
     // discarded.
     result._knownPresets = knownPresets.union(other.knownPresets);
     return result;
   }

   /// Returns a copy of this configuration with the given fields updated.
   ///
   /// Note that unlike [merge], this has no merging behavior—the old value is
   /// always replaced by the new one.
   Configuration change(
       {bool help,
       bool version,
       bool pauseAfterLoad,
       bool color,
       String configurationPath,
       String dart2jsPath,
       String reporter,
       int pubServePort,
       int concurrency,
       int shardIndex,
       int totalShards,
       Iterable<String> paths,
       Iterable<String> exceptPackages,
       Iterable<String> onlyPackages,
       Glob filename,
       Iterable<String> chosenPresets,
       Map<String, Configuration> presets,
       bool noRetry,

       // Suite-level configuration
       bool jsTrace,
       bool runSkipped,
       Iterable<String> dart2jsArgs,
       String precompiledPath,
       Iterable<Pattern> patterns,
       Iterable<TestPlatform> platforms,
       BooleanSelector includeTags,
       BooleanSelector excludeTags,
       Map<BooleanSelector, SuiteConfiguration> tags,
       Map<PlatformSelector, SuiteConfiguration> onPlatform,

       // Test-level configuration
       Timeout timeout,
       bool verboseTrace,
       bool chainStackTraces,
       bool skip,
       String skipReason,
       PlatformSelector testOn,
       Iterable<String> addTags}) {
     var config = new Configuration._(
         help: help ?? _help,
         version: version ?? _version,
         pauseAfterLoad: pauseAfterLoad ?? _pauseAfterLoad,
         color: color ?? _color,
         configurationPath: configurationPath ?? _configurationPath,
         dart2jsPath: dart2jsPath ?? _dart2jsPath,
         reporter: reporter ?? _reporter,
         pubServePort: pubServePort ?? pubServeUrl?.port,
         concurrency: concurrency ?? _concurrency,
         shardIndex: shardIndex ?? this.shardIndex,
         totalShards: totalShards ?? this.totalShards,
         paths: paths ?? _paths,
         foldTraceExcept: exceptPackages ?? _foldTraceExcept,
         foldTraceOnly: onlyPackages ?? _foldTraceOnly,
         filename: filename ?? _filename,
         chosenPresets: chosenPresets ?? this.chosenPresets,
         presets: presets ?? this.presets,
         noRetry: noRetry ?? _noRetry,
         suiteDefaults: suiteDefaults.change(
             jsTrace: jsTrace,
             runSkipped: runSkipped,
             dart2jsArgs: dart2jsArgs,
             precompiledPath: precompiledPath,
             patterns: patterns,
             platforms: platforms,
             includeTags: includeTags,
             excludeTags: excludeTags,
             tags: tags,
             onPlatform: onPlatform,
             timeout: timeout,
             verboseTrace: verboseTrace,
             chainStackTraces: chainStackTraces,
             skip: skip,
             skipReason: skipReason,
             testOn: testOn,
             addTags: addTags));
     return config._resolvePresets();
   }

   /// Merges two maps whose values are [Configuration]s.
   ///
   /// Any overlapping keys in the maps have their configurations merged in the
   /// returned map.
   Map<Object, Configuration> _mergeConfigMaps(
           Map<Object, Configuration> map1, Map<Object, Configuration> map2) =>
       mergeMaps(map1, map2,
           value: (config1, config2) => config1.merge(config2));

   /// Returns a copy of this [Configuration] with all [chosenPresets] resolved
   /// against [presets].
   Configuration _resolvePresets() {
     if (chosenPresets.isEmpty || presets.isEmpty) return this;

     var newPresets = new Map<String, Configuration>.from(presets);
     var merged = chosenPresets.fold(
         empty,
         (merged, preset) =>
             merged.merge(newPresets.remove(preset) ?? Configuration.empty));

     if (merged == empty) return this;
     var result = this.change(presets: newPresets).merge(merged);

     // Make sure the configuration knows about presets that were selected and
     // thus removed from [newPresets].
     result._knownPresets = new UnmodifiableSetView(
         result.knownPresets.toSet()..addAll(this.presets.keys));

     return result;
   }
 }
	// Copyright (c) 2015, 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.

	import 'dart:async';

	import 'package:boolean_selector/boolean_selector.dart';
	import 'package:collection/collection.dart';
	import 'package:glob/glob.dart';
	import 'package:path/path.dart' as p;

	import '../backend/platform_selector.dart';
	import '../backend/test_platform.dart';
	import '../frontend/timeout.dart';
	import '../util/io.dart';
	import 'configuration/args.dart' as args;
	import 'configuration/load.dart';
	import 'configuration/reporters.dart';
	import 'configuration/suite.dart';
	import 'configuration/values.dart';

	/// The key used to look up [Configuration.current] in a zone.
	final _currentKey = new Object();

	/// A class that encapsulates the command-line configuration of the test runner.
	class Configuration {
	/// An empty configuration with only default values.
	///
	/// Using this is slightly more efficient than manually constructing a new
	/// configuration with no arguments.
	static final empty = new Configuration._();

	/// The usage string for the command-line arguments.
	static String get usage => args.usage;

	/// Whether `--help` was passed.
	bool get help => _help ?? false;
	final bool _help;

	/// Whether `--version` was passed.
	bool get version => _version ?? false;
	final bool _version;

	/// Whether to pause for debugging after loading each test suite.
	bool get pauseAfterLoad => _pauseAfterLoad ?? false;
	final bool _pauseAfterLoad;

	/// The path to the file from which to load more configuration information.
	///
	/// This is not resolved automatically.
	String get configurationPath => _configurationPath ?? "dart_test.yaml";
	final String _configurationPath;

	/// The path to dart2js.
	String get dart2jsPath => _dart2jsPath ?? p.join(sdkDir, 'bin', 'dart2js');
	final String _dart2jsPath;

	/// The name of the reporter to use to display results.
	String get reporter => _reporter ?? defaultReporter;
	final String _reporter;

	/// Whether to disable retries of tests.
	bool get noRetry => _noRetry ?? false;
	final bool _noRetry;

	/// The URL for the `pub serve` instance from which to load tests, or `null`
	/// if tests should be loaded from the filesystem.
	final Uri pubServeUrl;

	/// Whether to use command-line color escapes.
	bool get color => _color ?? canUseSpecialChars;
	final bool _color;

	/// How many tests to run concurrently.
	int get concurrency =>
	pauseAfterLoad ? 1 : (_concurrency ?? defaultConcurrency);
	final int _concurrency;

	/// The index of the current shard, if sharding is in use, or `null` if it's
	/// not.
	///
	/// Sharding is a technique that allows the Google internal test framework to
	/// easily split a test run across multiple workers without requiring the
	/// tests to be modified by the user. When sharding is in use, the runner gets
	/// a shard index (this field) and a total number of shards, and is expected
	/// to provide the following guarantees:
	///
	/// * Running the same invocation of the runner, with the same shard index and
	/// total shards, will run the same set of tests.
	/// * Across all shards, each test must be run exactly once.
	///
	/// In addition, tests should be balanced across shards as much as possible.
	final int shardIndex;

	/// The total number of shards, if sharding is in use, or `null` if it's not.
	///
	/// See [shardIndex] for details.
	final int totalShards;

	/// The list of packages to fold when producing [StackTrace]s.
	Set<String> get foldTraceExcept => _foldTraceExcept ?? new Set();
	final Set<String> _foldTraceExcept;

	/// If non-empty, all packages not in this list will be folded when producing
	/// [StackTrace]s.
	Set<String> get foldTraceOnly => _foldTraceOnly ?? new Set();
	final Set<String> _foldTraceOnly;

	/// The paths from which to load tests.
	List<String> get paths => _paths ?? ["test"];
	final List<String> _paths;

	/// Whether the load paths were passed explicitly or the default was used.
	bool get explicitPaths => _paths != null;

	/// The glob matching the basename of tests to run.
	///
	/// This is used to find tests within a directory.
	Glob get filename => _filename ?? defaultFilename;
	final Glob _filename;

	/// The set of presets to use.
	///
	/// Any chosen presets for the parent configuration are added to the chosen
	/// preset sets for child configurations as well.
	///
	/// Note that the order of this set matters.
	final Set<String> chosenPresets;

	/// The set of tags that have been declared in any way in this configuration.
	Set<String> get knownTags {
	if (_knownTags != null) return _knownTags;

	var known = suiteDefaults.knownTags.toSet();
	for (var configuration in presets.values) {
	known.addAll(configuration.knownTags);
	}

	_knownTags = new UnmodifiableSetView(known);
	return _knownTags;
	}

	Set<String> _knownTags;

	/// Configuration presets.
	///
	/// These are configurations that can be explicitly selected by the user via
	/// the command line. Preset configuration takes precedence over the base
	/// configuration.
	///
	/// This is guaranteed not to have any keys that match [chosenPresets]; those
	/// are resolved when the configuration is constructed.
	final Map<String, Configuration> presets;

	/// All preset names that are known to be valid.
	///
	/// This includes presets that have already been resolved.
	Set<String> get knownPresets {
	if (_knownPresets != null) return _knownPresets;

	var known = presets.keys.toSet();
	for (var configuration in presets.values) {
	known.addAll(configuration.knownPresets);
	}

	_knownPresets = new UnmodifiableSetView(known);
	return _knownPresets;
	}

	Set<String> _knownPresets;

	/// The default suite-level configuration.
	final SuiteConfiguration suiteDefaults;

	/// Returns the current configuration, or a default configuration if no
	/// current configuration is set.
	///
	/// The current configuration is set using [asCurrent].
	static Configuration get current =>
	Zone.current[_currentKey] ?? new Configuration();

	/// Parses the configuration from [args].
	///
	/// Throws a [FormatException] if [args] are invalid.
	factory Configuration.parse(List<String> arguments) => args.parse(arguments);

	/// Loads the configuration from [path].
	///
	/// If [global] is `true`, this restricts the configuration file to only rules
	/// that are supported globally.
	///
	/// Throws an [IOException] if [path] does not exist or cannot be read. Throws
	/// a [FormatException] if its contents are invalid.
	factory Configuration.load(String path, {bool global: false}) =>
	load(path, global: global);

	factory Configuration(
	{bool help,
	bool version,
	bool pauseAfterLoad,
	bool color,
	String configurationPath,
	String dart2jsPath,
	String reporter,
	int pubServePort,
	int concurrency,
	int shardIndex,
	int totalShards,
	Iterable<String> paths,
	Iterable<String> foldTraceExcept,
	Iterable<String> foldTraceOnly,
	Glob filename,
	Iterable<String> chosenPresets,
	Map<String, Configuration> presets,
	bool noRetry,

	// Suite-level configuration
	bool jsTrace,
	bool runSkipped,
	Iterable<String> dart2jsArgs,
	String precompiledPath,
	Iterable<Pattern> patterns,
	Iterable<TestPlatform> platforms,
	BooleanSelector includeTags,
	BooleanSelector excludeTags,
	Map<BooleanSelector, SuiteConfiguration> tags,
	Map<PlatformSelector, SuiteConfiguration> onPlatform,

	// Test-level configuration
	Timeout timeout,
	bool verboseTrace,
	bool chainStackTraces,
	bool skip,
	int retry,
	String skipReason,
	PlatformSelector testOn,
	Iterable<String> addTags}) {
	var chosenPresetSet = chosenPresets?.toSet();
	var configuration = new Configuration._(
	help: help,
	version: version,
	pauseAfterLoad: pauseAfterLoad,
	color: color,
	configurationPath: configurationPath,
	dart2jsPath: dart2jsPath,
	reporter: reporter,
	pubServePort: pubServePort,
	concurrency: concurrency,
	shardIndex: shardIndex,
	totalShards: totalShards,
	paths: paths,
	foldTraceExcept: foldTraceExcept,
	foldTraceOnly: foldTraceOnly,
	filename: filename,
	chosenPresets: chosenPresetSet,
	presets: _withChosenPresets(presets, chosenPresetSet),
	noRetry: noRetry,
	suiteDefaults: new SuiteConfiguration(
	jsTrace: jsTrace,
	runSkipped: runSkipped,
	dart2jsArgs: dart2jsArgs,
	precompiledPath: precompiledPath,
	patterns: patterns,
	platforms: platforms,
	includeTags: includeTags,
	excludeTags: excludeTags,
	tags: tags,
	onPlatform: onPlatform,

	// Test-level configuration
	timeout: timeout,
	verboseTrace: verboseTrace,
	chainStackTraces: chainStackTraces,
	skip: skip,
	retry: retry,
	skipReason: skipReason,
	testOn: testOn,
	addTags: addTags));
	return configuration._resolvePresets();
	}

	static Map<Object, Configuration> _withChosenPresets(
	Map<Object, Configuration> map, Set<String> chosenPresets) {
	if (map == null \|\| chosenPresets == null) return map;
	return mapMap(map,
	value: (_, config) => config.change(
	chosenPresets: config.chosenPresets.union(chosenPresets)));
	}

	/// Creates new Configuration.
	///
	/// Unlike [new Configuration], this assumes [presets] is already resolved.
	Configuration._(
	{bool help,
	bool version,
	bool pauseAfterLoad,
	bool color,
	String configurationPath,
	String dart2jsPath,
	String reporter,
	int pubServePort,
	int concurrency,
	this.shardIndex,
	this.totalShards,
	Iterable<String> paths,
	Iterable<String> foldTraceExcept,
	Iterable<String> foldTraceOnly,
	Glob filename,
	Iterable<String> chosenPresets,
	Map<String, Configuration> presets,
	bool noRetry,
	SuiteConfiguration suiteDefaults})
	: _help = help,
	_version = version,
	_pauseAfterLoad = pauseAfterLoad,
	_color = color,
	_configurationPath = configurationPath,
	_dart2jsPath = dart2jsPath,
	_reporter = reporter,
	pubServeUrl = pubServePort == null
	? null
	: Uri.parse("http://localhost:$pubServePort"),
	_concurrency = concurrency,
	_paths = _list(paths),
	_foldTraceExcept = _set(foldTraceExcept),
	_foldTraceOnly = _set(foldTraceOnly),
	_filename = filename,
	chosenPresets =
	new UnmodifiableSetView(chosenPresets?.toSet() ?? new Set()),
	presets = _map(presets),
	_noRetry = noRetry,
	suiteDefaults = pauseAfterLoad == true
	? suiteDefaults?.change(timeout: Timeout.none) ??
	new SuiteConfiguration(timeout: Timeout.none)
	: suiteDefaults ?? SuiteConfiguration.empty {
	if (_filename != null && _filename.context.style != p.style) {
	throw new ArgumentError(
	"filename's context must match the current operating system, was "
	"${_filename.context.style}.");
	}

	if ((shardIndex == null) != (totalShards == null)) {
	throw new ArgumentError(
	"shardIndex and totalShards may only be passed together.");
	} else if (shardIndex != null) {
	RangeError.checkValueInInterval(
	shardIndex, 0, totalShards - 1, "shardIndex");
	}
	}

	/// Creates a new [Configuration] that takes its configuration from
	/// [SuiteConfiguration].
	factory Configuration.fromSuiteConfiguration(
	SuiteConfiguration suiteConfig) =>
	new Configuration._(suiteDefaults: suiteConfig);

	/// Returns an unmodifiable copy of [input].
	///
	/// If [input] is `null` or empty, this returns `null`.
	static List/<T>/ _list/<T>/(Iterable/<T>/ input) {
	if (input == null) return null;
	var list = new List/<T>/ .unmodifiable(input);
	if (list.isEmpty) return null;
	return list;
	}

	/// Returns a set from [input].
	static Set<T> _set<T>(Iterable<T> input) {
	if (input == null) return null;
	var set = new Set<T>.from(input);
	if (set.isEmpty) return null;
	return set;
	}

	/// Returns an unmodifiable copy of [input] or an empty unmodifiable map.
	static Map/<K, V>/ _map/<K, V>/(Map/<K, V>/ input) {
	if (input == null \|\| input.isEmpty) return const {};
	return new Map.unmodifiable(input);
	}

	/// Runs [body] with [this] as [Configuration.current].
	///
	/// This is zone-scoped, so [this] will be the current configuration in any
	/// asynchronous callbacks transitively created by [body].
	/=T/ asCurrent/<T>/(/=T/ body()) =>
	runZoned(body, zoneValues: {_currentKey: this});

	/// Merges this with [other].
	///
	/// For most fields, if both configurations have values set, [other]'s value
	/// takes precedence. However, certain fields are merged together instead.
	/// This is indicated in those fields' documentation.
	Configuration merge(Configuration other) {
	if (this == Configuration.empty) return other;
	if (other == Configuration.empty) return this;

	var foldTraceOnly = other._foldTraceOnly ?? _foldTraceOnly;
	var foldTraceExcept = other._foldTraceExcept ?? _foldTraceExcept;
	if (_foldTraceOnly != null) {
	if (other._foldTraceExcept != null) {
	foldTraceOnly = _foldTraceOnly.difference(other._foldTraceExcept);
	} else if (other._foldTraceOnly != null) {
	foldTraceOnly = other._foldTraceOnly.intersection(_foldTraceOnly);
	}
	} else if (_foldTraceExcept != null) {
	if (other._foldTraceOnly != null) {
	foldTraceOnly = other._foldTraceOnly.difference(_foldTraceExcept);
	} else if (other._foldTraceExcept != null) {
	foldTraceExcept = other._foldTraceExcept.union(_foldTraceExcept);
	}
	}

	var result = new Configuration._(
	help: other._help ?? _help,
	version: other._version ?? _version,
	pauseAfterLoad: other._pauseAfterLoad ?? _pauseAfterLoad,
	color: other._color ?? _color,
	configurationPath: other._configurationPath ?? _configurationPath,
	dart2jsPath: other._dart2jsPath ?? _dart2jsPath,
	reporter: other._reporter ?? _reporter,
	pubServePort: (other.pubServeUrl ?? pubServeUrl)?.port,
	concurrency: other._concurrency ?? _concurrency,
	shardIndex: other.shardIndex ?? shardIndex,
	totalShards: other.totalShards ?? totalShards,
	paths: other._paths ?? _paths,
	foldTraceExcept: foldTraceExcept,
	foldTraceOnly: foldTraceOnly,
	filename: other._filename ?? _filename,
	chosenPresets: chosenPresets.union(other.chosenPresets),
	presets: _mergeConfigMaps(presets, other.presets),
	noRetry: other._noRetry ?? _noRetry,
	suiteDefaults: suiteDefaults.merge(other.suiteDefaults));
	result = result._resolvePresets();

	// Make sure the merged config preserves any presets that were chosen and
	// discarded.
	result._knownPresets = knownPresets.union(other.knownPresets);
	return result;
	}

	/// Returns a copy of this configuration with the given fields updated.
	///
	/// Note that unlike [merge], this has no merging behavior—the old value is
	/// always replaced by the new one.
	Configuration change(
	{bool help,
	bool version,
	bool pauseAfterLoad,
	bool color,
	String configurationPath,
	String dart2jsPath,
	String reporter,
	int pubServePort,
	int concurrency,
	int shardIndex,
	int totalShards,
	Iterable<String> paths,
	Iterable<String> exceptPackages,
	Iterable<String> onlyPackages,
	Glob filename,
	Iterable<String> chosenPresets,
	Map<String, Configuration> presets,
	bool noRetry,

	// Suite-level configuration
	bool jsTrace,
	bool runSkipped,
	Iterable<String> dart2jsArgs,
	String precompiledPath,
	Iterable<Pattern> patterns,
	Iterable<TestPlatform> platforms,
	BooleanSelector includeTags,
	BooleanSelector excludeTags,
	Map<BooleanSelector, SuiteConfiguration> tags,
	Map<PlatformSelector, SuiteConfiguration> onPlatform,

	// Test-level configuration
	Timeout timeout,
	bool verboseTrace,
	bool chainStackTraces,
	bool skip,
	String skipReason,
	PlatformSelector testOn,
	Iterable<String> addTags}) {
	var config = new Configuration._(
	help: help ?? _help,
	version: version ?? _version,
	pauseAfterLoad: pauseAfterLoad ?? _pauseAfterLoad,
	color: color ?? _color,
	configurationPath: configurationPath ?? _configurationPath,
	dart2jsPath: dart2jsPath ?? _dart2jsPath,
	reporter: reporter ?? _reporter,
	pubServePort: pubServePort ?? pubServeUrl?.port,
	concurrency: concurrency ?? _concurrency,
	shardIndex: shardIndex ?? this.shardIndex,
	totalShards: totalShards ?? this.totalShards,
	paths: paths ?? _paths,
	foldTraceExcept: exceptPackages ?? _foldTraceExcept,
	foldTraceOnly: onlyPackages ?? _foldTraceOnly,
	filename: filename ?? _filename,
	chosenPresets: chosenPresets ?? this.chosenPresets,
	presets: presets ?? this.presets,
	noRetry: noRetry ?? _noRetry,
	suiteDefaults: suiteDefaults.change(
	jsTrace: jsTrace,
	runSkipped: runSkipped,
	dart2jsArgs: dart2jsArgs,
	precompiledPath: precompiledPath,
	patterns: patterns,
	platforms: platforms,
	includeTags: includeTags,
	excludeTags: excludeTags,
	tags: tags,
	onPlatform: onPlatform,
	timeout: timeout,
	verboseTrace: verboseTrace,
	chainStackTraces: chainStackTraces,
	skip: skip,
	skipReason: skipReason,
	testOn: testOn,
	addTags: addTags));
	return config._resolvePresets();
	}

	/// Merges two maps whose values are [Configuration]s.
	///
	/// Any overlapping keys in the maps have their configurations merged in the
	/// returned map.
	Map<Object, Configuration> _mergeConfigMaps(
	Map<Object, Configuration> map1, Map<Object, Configuration> map2) =>
	mergeMaps(map1, map2,
	value: (config1, config2) => config1.merge(config2));

	/// Returns a copy of this [Configuration] with all [chosenPresets] resolved
	/// against [presets].
	Configuration _resolvePresets() {
	if (chosenPresets.isEmpty \|\| presets.isEmpty) return this;

	var newPresets = new Map<String, Configuration>.from(presets);
	var merged = chosenPresets.fold(
	empty,
	(merged, preset) =>
	merged.merge(newPresets.remove(preset) ?? Configuration.empty));

	if (merged == empty) return this;
	var result = this.change(presets: newPresets).merge(merged);

	// Make sure the configuration knows about presets that were selected and
	// thus removed from [newPresets].
	result._knownPresets = new UnmodifiableSetView(
	result.knownPresets.toSet()..addAll(this.presets.keys));

	return result;
	}
	}