[flutter_plugin_tools] Make unit tests pass on Windows (#4149)

The purpose of this PR is to make running all unit tests on Windows pass (vs failing a large portion of the tests as currently happens). This does not mean that the commands actually work when run on Windows, or that Windows support is tested, only that it's possible to actually run the tests themselves. This is prep for actually supporting parts of the tool on Windows in future PRs.

Major changes:
- Make the tests significantly more hermetic:
  - Make almost all tools take a `Platform` constructor argument that can be used to inject a mock platform to control what OS the command acts like it is running on under test.
  - Add a path `Context` object to the base command, whose style matches the `Platform`, and use that almost everywhere instead of the top-level `path` functions.
  - In cases where Posix behavior is always required (such as parsing `git` output), explicitly use the `posix` context object for `path` functions.
- Start laying the groundwork for actual Windows support:
  - Replace all uses of `flutter` as a command with a getter that returns `flutter` or `flutter.bat` as appropriate.
  - For user messages that include relative paths, use a helper that always uses Posix-style relative paths for consistent output.

This bumps the version since quite a few changes have built up, and having a cut point before starting to make more changes to the commands to support Windows seems like a good idea.

Part of #86113

Author: stuartmorgan-g

script/tool/lib/src/analyze_command.dart

@@ -5,7 +5,7 @@
 import 'dart:async';
 
 import 'package:file/file.dart';
-import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
 
 import 'common/core.dart';
 import 'common/package_looping_command.dart';
@@ -19,7 +19,8 @@ class AnalyzeCommand extends PackageLoopingCommand {
   AnalyzeCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
-  }) : super(packagesDir, processRunner: processRunner) {
+    Platform platform = const LocalPlatform(),
+  }) : super(packagesDir, processRunner: processRunner, platform: platform) {
     argParser.addMultiOption(_customAnalysisFlag,
         help:
             'Directories (comma separated) that are allowed to have their own analysis options.',
@@ -57,9 +58,8 @@ class AnalyzeCommand extends PackageLoopingCommand {
 
       final bool allowed = (getStringListArg(_customAnalysisFlag)).any(
           (String directory) =>
-              directory != null &&
               directory.isNotEmpty &&
-              p.isWithin(
+              path.isWithin(
                   packagesDir.childDirectory(directory).path, file.path));
       if (allowed) {
         continue;
@@ -90,7 +90,7 @@ class AnalyzeCommand extends PackageLoopingCommand {
     });
     for (final Directory package in packageDirectories) {
       final int exitCode = await processRunner.runAndStream(
-          'flutter', <String>['packages', 'get'],
+          flutterCommand, <String>['packages', 'get'],
           workingDir: package);
       if (exitCode != 0) {
         return false;
@@ -109,7 +109,8 @@ class AnalyzeCommand extends PackageLoopingCommand {
 
     // Use the Dart SDK override if one was passed in.
     final String? dartSdk = argResults![_analysisSdk] as String?;
-    _dartBinaryPath = dartSdk == null ? 'dart' : p.join(dartSdk, 'bin', 'dart');
+    _dartBinaryPath =
+        dartSdk == null ? 'dart' : path.join(dartSdk, 'bin', 'dart');
   }
 
   @override

script/tool/lib/src/build_examples_command.dart

@@ -5,7 +5,7 @@
 import 'dart:async';
 
 import 'package:file/file.dart';
-import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
 
 import 'common/core.dart';
 import 'common/package_looping_command.dart';
@@ -23,7 +23,8 @@ class BuildExamplesCommand extends PackageLoopingCommand {
   BuildExamplesCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
-  }) : super(packagesDir, processRunner: processRunner) {
+    Platform platform = const LocalPlatform(),
+  }) : super(packagesDir, processRunner: processRunner, platform: platform) {
     argParser.addFlag(kPlatformLinux);
     argParser.addFlag(kPlatformMacos);
     argParser.addFlag(kPlatformWeb);
@@ -127,7 +128,7 @@ class BuildExamplesCommand extends PackageLoopingCommand {
 
     for (final Directory example in getExamplesForPlugin(package)) {
       final String packageName =
-          p.relative(example.path, from: packagesDir.path);
+          getRelativePosixPath(example, from: packagesDir);
 
       for (final _PlatformDetails platform in buildPlatforms) {
         String buildPlatform = platform.label;

script/tool/lib/src/common/package_looping_command.dart

@@ -8,6 +8,7 @@ import 'package:colorize/colorize.dart';
 import 'package:file/file.dart';
 import 'package:git/git.dart';
 import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
 
 import 'core.dart';
 import 'plugin_command.dart';
@@ -63,8 +64,10 @@ abstract class PackageLoopingCommand extends PluginCommand {
   PackageLoopingCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
+    Platform platform = const LocalPlatform(),
     GitDir? gitDir,
-  }) : super(packagesDir, processRunner: processRunner, gitDir: gitDir);
+  }) : super(packagesDir,
+            processRunner: processRunner, platform: platform, gitDir: gitDir);
 
   /// Packages that had at least one [logWarning] call.
   final Set<Directory> _packagesWithWarnings = <Directory>{};
@@ -158,8 +161,8 @@ abstract class PackageLoopingCommand extends PluginCommand {
   /// an exact format (e.g., published name, or basename) is required, that
   /// should be used instead.
   String getPackageDescription(Directory package) {
-    String packageName = p.relative(package.path, from: packagesDir.path);
-    final List<String> components = p.split(packageName);
+    String packageName = getRelativePosixPath(package, from: packagesDir);
+    final List<String> components = p.posix.split(packageName);
     // For the common federated plugin pattern of `foo/foo_subpackage`, drop
     // the first part since it's not useful.
     if (components.length == 2 &&
@@ -169,6 +172,16 @@ abstract class PackageLoopingCommand extends PluginCommand {
     return packageName;
   }
 
+  /// Returns the relative path from [from] to [entity] in Posix style.
+  ///
+  /// This should be used when, for example, printing package-relative paths in
+  /// status or error messages.
+  String getRelativePosixPath(
+    FileSystemEntity entity, {
+    required Directory from,
+  }) =>
+      p.posix.joinAll(path.split(path.relative(entity.path, from: from.path)));
+
   /// The suggested indentation for printed output.
   String get indentation => hasLongOutput ? '' : '  ';
 

script/tool/lib/src/common/plugin_command.dart

@@ -21,6 +21,7 @@ abstract class PluginCommand extends Command<void> {
   PluginCommand(
     this.packagesDir, {
     this.processRunner = const ProcessRunner(),
+    this.platform = const LocalPlatform(),
     GitDir? gitDir,
   }) : _gitDir = gitDir {
     argParser.addMultiOption(
@@ -79,6 +80,11 @@ abstract class PluginCommand extends Command<void> {
   /// This can be overridden for testing.
   final ProcessRunner processRunner;
 
+  /// The current platform.
+  ///
+  /// This can be overridden for testing.
+  final Platform platform;
+
   /// The git directory to use. If unset, [gitDir] populates it from the
   /// packages directory's enclosing repository.
   ///
@@ -88,9 +94,11 @@ abstract class PluginCommand extends Command<void> {
   int? _shardIndex;
   int? _shardCount;
 
+  /// A context that matches the default for [platform].
+  p.Context get path => platform.isWindows ? p.windows : p.posix;
+
   /// The command to use when running `flutter`.
-  String get flutterCommand =>
-      const LocalPlatform().isWindows ? 'flutter.bat' : 'flutter';
+  String get flutterCommand => platform.isWindows ? 'flutter.bat' : 'flutter';
 
   /// The shard of the overall command execution that this instance should run.
   int get shardIndex {
@@ -240,9 +248,9 @@ abstract class PluginCommand extends Command<void> {
               // plugins under 'my_plugin'. Also match if the exact plugin is
               // passed.
               final String relativePath =
-                  p.relative(subdir.path, from: dir.path);
-              final String packageName = p.basename(subdir.path);
-              final String basenamePath = p.basename(entity.path);
+                  path.relative(subdir.path, from: dir.path);
+              final String packageName = path.basename(subdir.path);
+              final String basenamePath = path.basename(entity.path);
               if (!excludedPlugins.contains(basenamePath) &&
                   !excludedPlugins.contains(packageName) &&
                   !excludedPlugins.contains(relativePath) &&

script/tool/lib/src/create_all_plugins_app_command.dart

@@ -5,6 +5,7 @@
 import 'dart:io' as io;
 
 import 'package:file/file.dart';
+import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 import 'package:pubspec_parse/pubspec_parse.dart';
 
@@ -51,7 +52,7 @@ class CreateAllPluginsAppCommand extends PluginCommand {
 
   Future<int> _createApp() async {
     final io.ProcessResult result = io.Process.runSync(
-      'flutter',
+      flutterCommand,
       <String>[
         'create',
         '--template=app',
@@ -156,7 +157,7 @@ class CreateAllPluginsAppCommand extends PluginCommand {
         <String, PathDependency>{};
 
     await for (final Directory package in getPlugins()) {
-      final String pluginName = package.path.split('/').last;
+      final String pluginName = package.basename;
       final File pubspecFile = package.childFile('pubspec.yaml');
       final Pubspec pubspec = Pubspec.parse(pubspecFile.readAsStringSync());
 
@@ -172,6 +173,7 @@ class CreateAllPluginsAppCommand extends PluginCommand {
 ### Generated file. Do not edit. Run `pub global run flutter_plugin_tools gen-pubspec` to update.
 name: ${pubspec.name}
 description: ${pubspec.description}
+publish_to: none
 
 version: ${pubspec.version}
 
@@ -197,7 +199,21 @@ dev_dependencies:${_pubspecMapString(pubspec.devDependencies)}
         buffer.write('  ${entry.key}: \n    sdk: ${dep.sdk}');
       } else if (entry.value is PathDependency) {
         final PathDependency dep = entry.value as PathDependency;
-        buffer.write('  ${entry.key}: \n    path: ${dep.path}');
+        String depPath = dep.path;
+        if (path.style == p.Style.windows) {
+          // Posix-style path separators are preferred in pubspec.yaml (and
+          // using a consistent format makes unit testing simpler), so convert.
+          final List<String> components = path.split(depPath);
+          final String firstComponent = components.first;
+          // path.split leaves a \ on drive components that isn't necessary,
+          // and confuses pub, so remove it.
+          if (firstComponent.endsWith(r':\')) {
+            components[0] =
+                firstComponent.substring(0, firstComponent.length - 1);
+          }
+          depPath = p.posix.joinAll(components);
+        }
+        buffer.write('  ${entry.key}: \n    path: $depPath');
       } else {
         throw UnimplementedError(
           'Not available for type: ${entry.value.runtimeType}',

script/tool/lib/src/drive_examples_command.dart

@@ -6,7 +6,7 @@ import 'dart:convert';
 import 'dart:io';
 
 import 'package:file/file.dart';
-import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
 
 import 'common/core.dart';
 import 'common/package_looping_command.dart';
@@ -22,7 +22,8 @@ class DriveExamplesCommand extends PackageLoopingCommand {
   DriveExamplesCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
-  }) : super(packagesDir, processRunner: processRunner) {
+    Platform platform = const LocalPlatform(),
+  }) : super(packagesDir, processRunner: processRunner, platform: platform) {
     argParser.addFlag(kPlatformAndroid,
         help: 'Runs the Android implementation of the examples');
     argParser.addFlag(kPlatformIos,
@@ -148,7 +149,7 @@ class DriveExamplesCommand extends PackageLoopingCommand {
     for (final Directory example in getExamplesForPlugin(package)) {
       ++examplesFound;
       final String exampleName =
-          p.relative(example.path, from: packagesDir.path);
+          getRelativePosixPath(example, from: packagesDir);
 
       final List<File> drivers = await _getDrivers(example);
       if (drivers.isEmpty) {
@@ -172,11 +173,10 @@ class DriveExamplesCommand extends PackageLoopingCommand {
 
         if (testTargets.isEmpty) {
           final String driverRelativePath =
-              p.relative(driver.path, from: package.path);
+              getRelativePosixPath(driver, from: package);
           printError(
               'Found $driverRelativePath, but no integration_test/*_test.dart files.');
-          errors.add(
-              'No test files for ${p.relative(driver.path, from: package.path)}');
+          errors.add('No test files for $driverRelativePath');
           continue;
         }
 
@@ -185,7 +185,7 @@ class DriveExamplesCommand extends PackageLoopingCommand {
             example, driver, testTargets,
             deviceFlags: deviceFlags);
         for (final File failingTarget in failingTargets) {
-          errors.add(p.relative(failingTarget.path, from: package.path));
+          errors.add(getRelativePosixPath(failingTarget, from: package));
         }
       }
     }
@@ -296,9 +296,9 @@ class DriveExamplesCommand extends PackageLoopingCommand {
             if (enableExperiment.isNotEmpty)
               '--enable-experiment=$enableExperiment',
             '--driver',
-            p.relative(driver.path, from: example.path),
+            getRelativePosixPath(driver, from: example),
             '--target',
-            p.relative(target.path, from: example.path),
+            getRelativePosixPath(target, from: example),
           ],
           workingDir: example);
       if (exitCode != 0) {

script/tool/lib/src/firebase_test_lab_command.dart

@@ -6,7 +6,7 @@ import 'dart:async';
 import 'dart:io' as io;
 
 import 'package:file/file.dart';
-import 'package:path/path.dart' as p;
+import 'package:platform/platform.dart';
 import 'package:uuid/uuid.dart';
 
 import 'common/core.dart';
@@ -21,16 +21,18 @@ class FirebaseTestLabCommand extends PackageLoopingCommand {
   FirebaseTestLabCommand(
     Directory packagesDir, {
     ProcessRunner processRunner = const ProcessRunner(),
-  }) : super(packagesDir, processRunner: processRunner) {
+    Platform platform = const LocalPlatform(),
+  }) : super(packagesDir, processRunner: processRunner, platform: platform) {
     argParser.addOption(
       'project',
       defaultsTo: 'flutter-infra',
       help: 'The Firebase project name.',
     );
     final String? homeDir = io.Platform.environment['HOME'];
     argParser.addOption('service-key',
-        defaultsTo:
-            homeDir == null ? null : p.join(homeDir, 'gcloud-service-key.json'),
+        defaultsTo: homeDir == null
+            ? null
+            : path.join(homeDir, 'gcloud-service-key.json'),
         help: 'The path to the service key for gcloud authentication.\n'
             r'If not provided, \$HOME/gcloud-service-key.json will be '
             r'assumed if $HOME is set.');
@@ -150,7 +152,7 @@ class FirebaseTestLabCommand extends PackageLoopingCommand {
     // test file's run.
     int resultsCounter = 0;
     for (final File test in _findIntegrationTestFiles(package)) {
-      final String testName = p.relative(test.path, from: package.path);
+      final String testName = getRelativePosixPath(test, from: package);
       print('Testing $testName...');
       if (!await _runGradle(androidDirectory, 'app:assembleDebug',
           testFile: test)) {
@@ -203,7 +205,7 @@ class FirebaseTestLabCommand extends PackageLoopingCommand {
       print('Running flutter build apk...');
       final String experiment = getStringArg(kEnableExperiment);
       final int exitCode = await processRunner.runAndStream(
-          'flutter',
+          flutterCommand,
           <String>[
             'build',
             'apk',