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

sdk/lib/_internal/pub_generated/test/implicit_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();
-
-  forBothPubGetAndUpgrade((command) {
-    integration("implicitly constrains it to versions pub supports", () {
-      servePackages((builder) {
-        builder.serve("barback", current("barback"));
-        builder.serve("stack_trace", previous("stack_trace"));
-        builder.serve("stack_trace", current("stack_trace"));
-        builder.serve("stack_trace", nextPatch("stack_trace"));
-        builder.serve("stack_trace", max("stack_trace"));
-        builder.serve("source_span", current("source_span"));
-      });
-
-      d.appDir({
-        "barback": "any"
-      }).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "stack_trace": nextPatch("stack_trace")
-      }).validate();
-    });
-
-    integration(
-        "pub's implicit constraint uses the same source and "
-            "description as a dependency override",
-        () {
-      servePackages((builder) {
-        builder.serve("barback", current("barback"));
-        builder.serve("stack_trace", nextPatch("stack_trace"));
-        builder.serve("source_span", current("source_span"));
-      });
-
-      d.dir(
-          "stack_trace",
-          [
-              d.libDir("stack_trace", 'stack_trace ${current("stack_trace")}'),
-              d.libPubspec("stack_trace", current("stack_trace"))]).create();
-
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "dependencies": {
-            "barback": "any"
-          },
-          "dependency_overrides": {
-            "stack_trace": {
-              "path": "../stack_trace"
-            },
-          }
-        })]).create();
-
-      pubCommand(command);
-
-      // Validate that we're using the path dependency version of stack_trace
-      // rather than the hosted version.
-      d.packagesDir({
-        "stack_trace": current("stack_trace")
-      }).validate();
-    });
-
-    integration(
-        "doesn't add a constraint if barback isn't in the package " "graph",
-        () {
-      servePackages((builder) {
-        builder.serve("stack_trace", previous("stack_trace"));
-        builder.serve("stack_trace", current("stack_trace"));
-        builder.serve("stack_trace", nextPatch("stack_trace"));
-        builder.serve("stack_trace", max("stack_trace"));
-        builder.serve("source_span", current("source_span"));
-      });
-
-      d.appDir({
-        "stack_trace": "any"
-      }).create();
-
-      pubCommand(command);
-
-      d.packagesDir({
-        "stack_trace": max("stack_trace")
-      }).validate();
-    });
-  });
-
-  integration(
-      "unlocks if the locked version doesn't meet pub's " "constraint",
-      () {
-    servePackages((builder) {
-      builder.serve("barback", current("barback"));
-      builder.serve("stack_trace", previous("stack_trace"));
-      builder.serve("stack_trace", current("stack_trace"));
-      builder.serve("source_span", current("source_span"));
-    });
-
-    d.appDir({
-      "barback": "any"
-    }).create();
-
-    // Hand-create a lockfile to pin the package to an older version.
-    createLockFile("myapp", hosted: {
-      "barback": current("barback"),
-      "stack_trace": previous("stack_trace")
-    });
-
-    pubGet();
-
-    // It should be upgraded.
-    d.packagesDir({
-      "stack_trace": current("stack_trace")
-    }).validate();
-  });
-}
-
-String current(String packageName) =>
-    barback.pubConstraints[packageName].min.toString();
-
-String previous(String packageName) {
-  var constraint = barback.pubConstraints[packageName];
-  return new Version(
-      constraint.min.major,
-      constraint.min.minor - 1,
-      0).toString();
-}
-
-String nextPatch(String packageName) =>
-    barback.pubConstraints[packageName].min.nextPatch.toString();
-
-String max(String packageName) =>
-    barback.pubConstraints[packageName].max.toString();