Add DatastoreDB.replace({defaultPartition})

test/db/db_test.dart

+// Copyright (c) 2015, 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.
+
+library gcloud.db_test;
+
+import 'package:gcloud/db.dart';
+import 'package:unittest/unittest.dart';
+
+@Kind()
+class Foobar extends Model {}
+
+main() {
+  group('db', () {
+    test('default-partition', () {
+      var db = new DatastoreDB(null);
+
+      // Test defaultPartition
+      expect(db.defaultPartition.namespace, isNull);
+
+      // Test emptyKey
+      expect(db.emptyKey.partition.namespace, isNull);
+
+      // Test emptyKey.append()
+      var key = db.emptyKey.append(Foobar, id: 42);
+      expect(key.parent, db.emptyKey);
+      expect(key.partition.namespace, isNull);
+      expect(key.id, 42);
+      expect(key.type, equals(Foobar));
+    });
+
+    test('non-default-partition', () {
+      var nsDb = new DatastoreDB(
+          null, defaultPartition: new Partition('foobar-namespace'));
+
+      // Test defaultPartition
+      expect(nsDb.defaultPartition.namespace, 'foobar-namespace');
+
+      // Test emptyKey
+      expect(nsDb.emptyKey.partition.namespace, 'foobar-namespace');
+
+      // Test emptyKey.append()
+      var key = nsDb.emptyKey.append(Foobar, id: 42);
+      expect(key.parent, nsDb.emptyKey);
+      expect(key.partition.namespace, 'foobar-namespace');
+      expect(key.id, 42);
+      expect(key.type, equals(Foobar));
+    });
+  });
+}