cpsir unittests: move all unittests into individual files and test runners.

tests/compiler/dart2js/cps_ir/up_to_date_test.dart

+// Copyright (c) 2016, 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.
+
+/// Test that cps_ir/update_all.dart and every cps_ir/*_test.dart file are up to
+/// date. There should be a line in update_all and a file in the cps_ir folder
+/// for each test file in the `input/` folder.
+library tests.compiler.dart2js.cps_ir.up_to_date_test;
+
+import 'dart:io';
+
+main(args) {
+  bool update = args.length > 0 && args[0] == 'update';
+  var inputDir = new Directory.fromUri(Platform.script.resolve('input'));
+
+  bool errorsFound = false;
+
+  // Note: we create a test file per input file because invoking dart2js many
+  // times on a single test often makes test.py timeout.
+  //
+  // We tried using multi-tests for this, but it is unfortunately brittle. For
+  // example, multi-tests can't import code from one folder above the current
+  // directory, which prevents us from putting generated tests under a different
+  // folder than the rest of the helpers (like memory_compiler.dart)
+  var files = inputDir.listSync().map((f) => f.uri.pathSegments.last).toList();
+  files.sort();
+  for (var file in files) {
+    var testFilename = file.replaceAll('.dart', '_test.dart');
+    var contents = generateTestFile(file);
+    if (checkAndMaybeUpdate(testFilename, contents, update)) errorsFound = true;
+  }
+
+  var updateAllContents = generateUpdateAllFile(files);
+  if (checkAndMaybeUpdate('update_all.dart', updateAllContents, update)) {
+    errorsFound = true;
+  }
+
+  if (errorsFound) {
+    print(regenerateMessage);
+    exit(1);
+  }
+}
+
+bool checkAndMaybeUpdate(String filename, String contents,
+    bool update) {
+  var testFile = new File.fromUri(Platform.script.resolve(filename));
+  bool exists = testFile.existsSync();
+  var isUpToDate = exists && testFile.readAsStringSync() == contents;
+  if (isUpToDate) {
+    print('PASS: ${filename} is up to date.');

[Kevin Millikin (Google), 2016/01/12 17:45:48]

I think the focus of these messages should be on the fact that the test did or
did not match expectations (not on updating the expectation).  Suggest:

PASS: $filename matches the expectation

INFO: $filename was updated

FAILED: {$exists ? 'unexpected JavaScript code' : 'missing expectation'} for
$filename

+  } else if (update) {
+    testFile.writeAsStringSync(contents);
+    print('INFO: ${filename} was updated.');
+  } else {
+    print("FAILED: ${filename} is ${exists ? 'out of date' : 'missing'}");
+    return true;
+  }
+  return false;
+}
+
+String generateUpdateAllFile(List<String> files) {
+  var lines = files.map((f) => "runTest('$f', update: true);");
+  return '''
+// ---- AUTO-GENERATED -------------------
+// This file was autogenerated by running:
+//
+//     dart path/to/${Platform.script.pathSegments.last} update
+//
+// Do not edit this file by hand.
+// ---------------------------------------
+
+library tests.compiler.dart2js.cps_ir.update_all;
+
+import 'runner.dart';
+
+main(args) {
+  ${lines.join('\n  ')}
+}
+''';
+}
+
+String generateTestFile(String file) => '''
+// ---- AUTO-GENERATED -------------------
+// This file was autogenerated by running:
+//
+//     dart path/to/${Platform.script.pathSegments.last} update
+//
+// Do not edit this file by hand.
+// ---------------------------------------
+
+library tests.compiler.dart2js.cps_ir.$file;
+
+import 'runner.dart';
+
+main(args) {
+  runTest("$file", update: args.length > 0 && args[0] == "update");
+}
+''';
+
+
+String get regenerateMessage {
+  var flags = Platform.packageRoot == null
+    ? '' : '--package-root=${Platform.packageRoot} ';
+  return '''
+
+To regenerate the test files, please run:
+  dart $flags${Platform.script} update''';
+}