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

sdk/lib/_internal/pub_generated/test/implicit_barback_dependency_test.dart

-// Copyright (c) 2013, 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 'package:pub_semver/pub_semver.dart';
-
-import 'descriptor.dart' as d;
-import 'test_pub.dart';
-import '../lib/src/barback.dart' as barback;
-
-main() {
-  initConfig();
-
-  var constraint = barback.pubConstraints["barback"];
-  var current = constraint.min.toString();
-  var previous =
-      new Version(constraint.min.major, constraint.min.minor - 1, 0).toString();
-  var nextPatch = constraint.min.nextPatch.toString();
-  var max = constraint.max.toString();
-
-  var sourceSpanVersion = barback.pubConstraints["source_span"].min.toString();
-  var stackTraceVersion = barback.pubConstraints["stack_trace"].min.toString();
-
-  forBothPubGetAndUpgrade((command) {
-    integration("implicitly constrains barback to versions pub supports", () {
-      servePackages((builder) {
-        builder.serve("barback", previous);
-        builder.serve("barback", current);
-        builder.serve("barback", nextPatch);
-        builder.serve("barback", max);
-        builder.serve("source_span", sourceSpanVersion);
-        builder.serve("stack_trace", stackTraceVersion);
-      });
-
-      d.appDir({
-        "barback": "any"
-      }).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "barback": nextPatch
-      }).validate();
-    });
-
-    integration("discovers transitive dependency on barback", () {
-      servePackages((builder) {
-        builder.serve("barback", previous);
-        builder.serve("barback", current);
-        builder.serve("barback", nextPatch);
-        builder.serve("barback", max);
-        builder.serve("source_span", sourceSpanVersion);
-        builder.serve("stack_trace", stackTraceVersion);
-      });
-
-      d.dir(
-          "foo",
-          [d.libDir("foo", "foo 0.0.1"), d.libPubspec("foo", "0.0.1", deps: {
-          "barback": "any"
-        })]).create();
-
-      d.appDir({
-        "foo": {
-          "path": "../foo"
-        }
-      }).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "barback": nextPatch,
-        "foo": "0.0.1"
-      }).validate();
-    });
-
-    integration(
-        "pub's implicit constraint uses the same source and "
-            "description as a dependency override",
-        () {
-      servePackages((builder) {
-        builder.serve("source_span", sourceSpanVersion);
-        builder.serve("stack_trace", stackTraceVersion);
-      });
-
-      d.dir(
-          'barback',
-          [
-              d.libDir('barback', 'barback $current'),
-              d.libPubspec('barback', current),]).create();
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependency_overrides": {
-            "barback": {
-              "path": "../barback"
-            }
-          }
-        })]).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "barback": current
-      }).validate();
-    });
-  });
-
-  integration("unlock if the locked version doesn't meet pub's constraint", () {
-    servePackages((builder) {
-      builder.serve("barback", previous);
-      builder.serve("barback", current);
-      builder.serve("source_span", sourceSpanVersion);
-      builder.serve("stack_trace", stackTraceVersion);
-    });
-
-    d.appDir({
-      "barback": "any"
-    }).create();
-
-    // Hand-create a lockfile to pin barback to an older version.
-    createLockFile("myapp", hosted: {
-      "barback": previous
-    });
-
-    pubGet();
-
-    // It should be upgraded.
-    d.packagesDir({
-      "barback": current
-    }).validate();
-  });
-
-  integration(
-      "includes pub in the error if a solve failed because there "
-          "is no version available",
-      () {
-    servePackages((builder) {
-      builder.serve("barback", previous);
-      builder.serve("source_span", sourceSpanVersion);
-      builder.serve("stack_trace", stackTraceVersion);
-    });
-
-    d.appDir({
-      "barback": "any"
-    }).create();
-
-    pubGet(error: """
-Package barback 0.12.0 does not match >=$current <$max derived from:
-- myapp 0.0.0 depends on version any
-- pub itself depends on version >=$current <$max""");
-  });
-
-  integration(
-      "includes pub in the error if a solve failed because there "
-          "is a disjoint constraint",
-      () {
-    servePackages((builder) {
-      builder.serve("barback", previous);
-      builder.serve("barback", current);
-      builder.serve("source_span", sourceSpanVersion);
-      builder.serve("stack_trace", stackTraceVersion);
-    });
-
-    d.appDir({
-      "barback": previous
-    }).create();
-
-    pubGet(error: """
-Incompatible version constraints on barback:
-- myapp 0.0.0 depends on version $previous
-- pub itself depends on version >=$current <$max""");
-  });
-}