Hook up dependency overrides to the rest of pub.

sdk/lib/_internal/pub/test/validator/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 '../../lib/src/entrypoint.dart';
+import '../../lib/src/validator.dart';
+import '../../lib/src/validator/dependency_override.dart';
+import '../descriptor.dart' as d;
+import '../test_pub.dart';
+import 'utils.dart';
+
+Validator dependencyOverride(Entrypoint entrypoint) =>
+    new DependencyOverrideValidator(entrypoint);
+
+main() {
+  initConfig();
+
+  integration('invalidates a package if it has dependency overrides', () {
+    d.dir(appPath, [
+      d.pubspec({
+        "name": "myapp",
+        "dependency_overrides": {
+          "foo": "<3.0.0"
+        }
+      })
+    ]).create();
+
+    expectValidationError(dependencyOverride);
+  });
+}