Revert "Revert "Use native async/await support in pub.""

sdk/lib/_internal/pub_generated/test/barback/utils.dart

-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS d.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 'package:scheduled_test/scheduled_test.dart';
-
-import '../../lib/src/exit_codes.dart' as exit_codes;
-import '../test_pub.dart';
-
-/// Runs separate integration tests for "pub build", "pub serve", and
-/// "pub build --format json" and validates that in all cases, it fails with
-/// an expected error message and exits with [exitCode].
-///
-/// The integrations assume set up is already done, so you will likely want to
-/// call [setUp] before this.
-///
-/// If [error] is provided, then both pub build and pub serve should exit with
-/// that message. Otherwise, [buildError] is the expected error from pub build
-/// and [serveError] from pub serve.
-void pubBuildAndServeShouldFail(String description, {List<String> args,
-    String error, String buildError, String serveError, int exitCode}) {
-
-  if (error != null) {
-    assert(buildError == null);
-    buildError = error;
-
-    assert(serveError == null);
-    serveError = error;
-  }
-
-  // Usage errors also print the usage, so validate that.
-  var buildExpectation = buildError;
-  var serveExpectation = serveError;
-  if (exitCode == exit_codes.USAGE) {
-    buildExpectation =
-        allOf(startsWith(buildExpectation), contains("Usage: pub build"));
-    serveExpectation =
-        allOf(startsWith(serveExpectation), contains("Usage: pub serve"));
-  }
-
-  integration("build fails $description", () {
-    schedulePub(
-        args: ["build"]..addAll(args),
-        error: buildExpectation,
-        exitCode: exitCode);
-  });
-
-  integration("build --format json fails $description", () {
-    schedulePub(args: ["build", "--format", "json"]..addAll(args), outputJson: {
-      "error": buildError // No usage in JSON output.
-    }, exitCode: exitCode);
-  });
-
-  integration("serve fails $description", () {
-    schedulePub(
-        args: ["serve"]..addAll(args),
-        error: serveExpectation,
-        exitCode: exitCode);
-  });
-}