diff --git a/pkg/front_end/tool/fasta.dart b/pkg/front_end/tool/fasta.dart
new file mode 100644
index 0000000..77f1115
--- /dev/null
+++ b/pkg/front_end/tool/fasta.dart
@@ -0,0 +1,108 @@
+// Copyright (c) 2019, 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:io';
+
+final String repoDir = _computeRepoDir();
+
+final String toolDir = '$repoDir/pkg/front_end/tool/_fasta';
+
+final String kernelBin = '$repoDir/pkg/kernel/bin';
+
+String get dartVm =>
+    Platform.isWindows ? '$repoDir/sdk/bin/dart.bat' : '$repoDir/sdk/bin/dart';
+
+main(List<String> args) async {
+  List<String> extraVmArguments = [];
+  String script;
+  List<String> scriptArguments = [];
+
+  int index = 0;
+  for (; index < args.length; index++) {
+    String arg = args[index];
+    if (arg.startsWith('-')) {
+      extraVmArguments.add(arg);
+    } else {
+      break;
+    }
+  }
+  if (args.length == index) {
+    stop("No command provided.");
+  }
+  String command = args[index++];
+  List<String> remainingArguments = args.skip(index).toList();
+
+  switch (command) {
+    case 'abcompile':
+      script = '${toolDir}/abcompile.dart';
+      break;
+    case 'compile':
+      script = '${toolDir}/compile.dart';
+      break;
+    case 'compile-platform':
+      script = '${toolDir}/compile_platform.dart';
+      break;
+    case 'log':
+      script = '${toolDir}/log_analyzer.dart';
+      break;
+    case 'logd':
+      script = '${toolDir}/log_collector.dart';
+      break;
+    case 'outline':
+      script = '${toolDir}/outline.dart';
+      break;
+    case 'parser':
+      script = '${toolDir}/parser.dart';
+      break;
+    case 'scanner':
+      script = '${toolDir}/scanner.dart';
+      break;
+    case 'dump-partial':
+      script = '${toolDir}/dump_partial.dart';
+      break;
+    case 'dump-ir':
+      script = '${kernelBin}/dump.dart';
+      if (remainingArguments.isEmpty || remainingArguments.length > 2) {
+        stop("Usage: $command dillfile [output]");
+      }
+      break;
+    case 'testing':
+      script = '${repoDir}/pkg/testing/bin/testing.dart';
+      scriptArguments.add('--config=${repoDir}/pkg/front_end/testing.json');
+      break;
+    case 'generate-messages':
+      script = '${toolDir}/generate_messages.dart';
+      break;
+    case 'generate-experimental-flags':
+      script = '${toolDir}/generate_experimental_flags.dart';
+      break;
+    default:
+      stop("'$command' isn't a valid subcommand.");
+  }
+
+  List<String> arguments = [];
+  arguments.addAll(extraVmArguments);
+  arguments.add('--enable-asserts');
+  arguments.add(script);
+  arguments.addAll(remainingArguments);
+  arguments.addAll(scriptArguments);
+
+  print('Running: ${dartVm} ${arguments.join(' ')}');
+  Process process = await Process.start(dartVm, arguments,
+      mode: ProcessStartMode.inheritStdio);
+  exitCode = await process.exitCode;
+}
+
+String _computeRepoDir() {
+  ProcessResult result = Process.runSync(
+      'git', ['rev-parse', '--show-toplevel'],
+      runInShell: true,
+      workingDirectory: new File.fromUri(Platform.script).parent.path);
+  return (result.stdout as String).trim();
+}
+
+void stop(String message) {
+  stderr.write(message);
+  exit(2);
+}
diff --git a/pkg/testing/lib/src/run_tests.dart b/pkg/testing/lib/src/run_tests.dart
index ce0849d..5d6e27d 100644
--- a/pkg/testing/lib/src/run_tests.dart
+++ b/pkg/testing/lib/src/run_tests.dart
@@ -82,6 +82,12 @@
     String configurationPath;
     if (configurationPaths.length == 1) {
       configurationPath = configurationPaths.single;
+      File file = new File(configurationPath);
+      if (await file.exists()) {
+        // If [configurationPath] exists as a file, use the absolute URI. This
+        // handles absolute paths on Windows.
+        configurationPath = file.absolute.uri.toString();
+      }
     } else {
       configurationPath = "testing.json";
       if (!await new File(configurationPath).exists()) {