Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/dependency_override_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:path/path.dart' as path;
-
-import 'descriptor.dart' as d;
-import 'test_pub.dart';
-
-main() {
-  initConfig();
-  forBothPubGetAndUpgrade((command) {
-    integration("chooses best version matching override constraint", () {
-      servePackages((builder) {
-        builder.serve("foo", "1.0.0");
-        builder.serve("foo", "2.0.0");
-        builder.serve("foo", "3.0.0");
-      });
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependencies": {
-            "foo": ">2.0.0"
-          },
-          "dependency_overrides": {
-            "foo": "<3.0.0"
-          }
-        })]).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "foo": "2.0.0"
-      }).validate();
-    });
-
-    integration("treats override as implicit dependency", () {
-      servePackages((builder) {
-        builder.serve("foo", "1.0.0");
-      });
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependency_overrides": {
-            "foo": "any"
-          }
-        })]).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "foo": "1.0.0"
-      }).validate();
-    });
-
-    integration("ignores other constraints on overridden package", () {
-      servePackages((builder) {
-        builder.serve("foo", "1.0.0");
-        builder.serve("foo", "2.0.0");
-        builder.serve("foo", "3.0.0");
-        builder.serve("bar", "1.0.0", pubspec: {
-          "dependencies": {
-            "foo": "5.0.0-nonexistent"
-          }
-        });
-      });
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependencies": {
-            "bar": "any"
-          },
-          "dependency_overrides": {
-            "foo": "<3.0.0"
-          }
-        })]).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "foo": "2.0.0",
-        "bar": "1.0.0"
-      }).validate();
-    });
-
-    integration("warns about overridden dependencies", () {
-      servePackages((builder) {
-        builder.serve("foo", "1.0.0");
-        builder.serve("bar", "1.0.0");
-      });
-
-      d.dir("baz", [d.libDir("baz"), d.libPubspec("baz", "0.0.1")]).create();
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependency_overrides": {
-            "foo": "any",
-            "bar": "any",
-            "baz": {
-              "path": "../baz"
-            }
-          }
-        })]).create();
-
-      var bazPath = path.join("..", "baz");
-
-      schedulePub(args: [command.name], output: command.success, error: """
-          Warning: You are using these overridden dependencies:
-          ! bar 1.0.0
-          ! baz 0.0.1 from path $bazPath
-          ! foo 1.0.0
-          """);
-    });
-  });
-}