Store the async-await compiled pub code directly in the repo.

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

+library pub_tests;
+import 'dart:convert';
+import 'descriptor.dart' as d;
+import 'test_pub.dart';
+main() {
+  initConfig();
+  forBothPubGetAndUpgrade((command) {
+    integration('fails gracefully on a dependency from an unknown source', () {
+      d.appDir({
+        "foo": {
+          "bad": "foo"
+        }
+      }).create();
+      pubCommand(
+          command,
+          error: 'Package myapp depends on foo from unknown source "bad".');
+    });
+    integration(
+        'fails gracefully on transitive dependency from an unknown ' 'source',
+        () {
+      d.dir(
+          'foo',
+          [d.libDir('foo', 'foo 0.0.1'), d.libPubspec('foo', '0.0.1', deps: {
+          "bar": {
+            "bad": "bar"
+          }
+        })]).create();
+      d.appDir({
+        "foo": {
+          "path": "../foo"
+        }
+      }).create();
+      pubCommand(
+          command,
+          error: 'Package foo depends on bar from unknown source "bad".');
+    });
+    integration('ignores unknown source in lockfile', () {
+      d.dir('foo', [d.libDir('foo'), d.libPubspec('foo', '0.0.1')]).create();
+      d.dir(appPath, [d.appPubspec({
+          "foo": {
+            "path": "../foo"
+          }
+        })]).create();
+      d.dir(appPath, [d.file("pubspec.lock", JSON.encode({
+          'packages': {
+            'foo': {
+              'version': '0.0.0',
+              'source': 'bad',
+              'description': {
+                'name': 'foo'
+              }
+            }
+          }
+        }))]).create();
+      pubCommand(command);
+      d.dir(
+          packagesPath,
+          [d.dir("foo", [d.file("foo.dart", 'main() => "foo";')])]).validate();
+    });
+  });
+}