[dart2js] Add test for deferred loading bundling.

Change-Id: I8720eed34551dbf06364c50ab01cef752a1aca58
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/309462
Reviewed-by: Stephen Adams <sra@google.com>
Commit-Queue: Nate Biggs <natebiggs@google.com>

pkg/compiler/test/end_to_end/bundle_parts_test.dart

@@ -0,0 +1,60 @@
+// Copyright (c) 2023, 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.
+
+// Ensure that bundling part files into the same file still allows them to load
+// correctly.
+
+import 'dart:io';
+
+import 'package:expect/expect.dart';
+
+import '../helpers/d8_helper.dart';
+
+const String verifyParts = '''
+if (!\$__dart_deferred_initializers__) {
+  throw 'Did not intialize \$__dart_deferred_initializers__';
+}
+// Expect 'eventLog', 'current', and 2 hashes for part files.
+if (Object.keys(\$__dart_deferred_initializers__).length != 4) {
+  var data =  JSON.stringify(\$__dart_deferred_initializers__);
+  throw '\$__dart_deferred_initializers__ has unexpected format: ' + data;
+}
+''';
+
+const List<String> dataFiles = [
+  'deferred_lib1.dart',
+  'deferred_lib2.dart',
+  'deferred_main.dart'
+];
+
+Future<Directory> createTempDir() {
+  return Directory.systemTemp.createTemp('dart2js_bundle_parts_test-');
+}
+
+Future<void> runTestWithOptions(List<String> options) async {
+  print('Running with flags: $options');
+  final tmpDir = await createTempDir();
+  Uri inUri = Platform.script.resolve('deferred_data/deferred_main.dart');
+  Uri outUri = tmpDir.uri.resolve('out.js');
+  await getCompilationResultsForD8(inUri, outUri, options: options);
+  final part1 = File(tmpDir.uri.resolve('out.js_1.part.js').toFilePath());
+  final part2 = File(tmpDir.uri.resolve('out.js_2.part.js').toFilePath());
+  final bundledPartsUri = tmpDir.uri.resolve('out.bundle.js');
+  final bundledParts = File(bundledPartsUri.toFilePath());
+  await bundledParts.writeAsBytes(await part1.readAsBytes());
+  await bundledParts.writeAsBytes(await part2.readAsBytes(),
+      mode: FileMode.append);
+  await bundledParts.writeAsString('\n$verifyParts', mode: FileMode.append);
+  final result = await executeJsWithD8(bundledPartsUri);
+  if (result.exitCode != 0) {
+    Expect.fail('Expected exit code 0. D8 results:\n'
+        '${(result.stdout as String).trim()}');
+  }
+  Expect.equals(0, result.exitCode);
+}
+
+void main() async {
+  await runTestWithOptions([]);
+  await runTestWithOptions(['--minify']);
+}

pkg/compiler/test/end_to_end/deferred_data/deferred_lib1.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2023, 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.
+
+class Class1 {
+  method() => 'Class1.method';
+}

pkg/compiler/test/end_to_end/deferred_data/deferred_lib2.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2023, 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.
+
+class Class2 {
+  method() => 'Class2.method';
+}

pkg/compiler/test/end_to_end/deferred_data/deferred_main.dart

@@ -0,0 +1,12 @@
+// Copyright (c) 2023, 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 'deferred_lib1.dart' deferred as lib1;
+import 'deferred_lib2.dart' deferred as lib2;
+
+main() async {
+  await lib1.loadLibrary();
+  print(new lib1.Class1().method());
+  print(new lib2.Class2().method());
+}

pkg/compiler/test/helpers/d8_helper.dart

@@ -43,10 +43,24 @@ Future<D8Result> runWithD8(
   entryPoint ??= Uri.parse('memory:main.dart');
   Uri mainFile =
       await createTemp(entryPoint, memorySourceFiles, printSteps: printSteps);
-  String output = uriPathToNative(mainFile.resolve('out.js').path);
+  Uri output = nativeToUri(mainFile.resolve('out.js').path);
+
+  CompilationResult compilationResult = await getCompilationResultsForD8(
+      mainFile, output,
+      options: options, printJs: printJs, printSteps: printSteps);
+  final d8Result = executeJsWithD8(output,
+      expectedOutput: expectedOutput, printSteps: printSteps);
+  return D8Result(compilationResult, d8Result, output.toFilePath());
+}
+
+Future<CompilationResult> getCompilationResultsForD8(
+    Uri mainFile, Uri outputFile,
+    {List<String> options = const <String>[],
+    bool printJs = false,
+    bool printSteps = false}) async {
   List<String> dart2jsArgs = [
     mainFile.toString(),
-    '-o$output',
+    '-o${outputFile.toFilePath()}',
     if (Platform.packageConfig != null) '--packages=${Platform.packageConfig}',
     ...options,
     if (options.contains(Flags.noSoundNullSafety))
@@ -60,12 +74,16 @@ Future<D8Result> runWithD8(
   Expect.isTrue(result.isSuccess);
   if (printJs) {
     print('dart2js output:');
-    print(new File(output).readAsStringSync());
+    print(new File(outputFile.toFilePath()).readAsStringSync());
   }
+  return result;
+}
 
+ProcessResult executeJsWithD8(Uri jsFile,
+    {String? expectedOutput, bool printSteps = false}) {
   List<String> d8Args = [
     '$sdkPath/_internal/js_runtime/lib/preambles/d8.js',
-    output
+    jsFile.toFilePath()
   ];
   if (printSteps) print('Running: d8 ${d8Args.join(' ')}');
   ProcessResult runResult = Process.runSync(d8executable, d8Args);
@@ -77,7 +95,7 @@ Future<D8Result> runWithD8(
     Expect.stringEquals(expectedOutput.trim(),
         runResult.stdout.replaceAll('\r\n', '\n').trim());
   }
-  return D8Result(result, runResult, output);
+  return runResult;
 }
 
 class D8Result {