Allow class-specific creation of symmetric VKeys (#625)

* Allow class-specific creation of symmetrict VKeys

When translating from a datastore Key to a VKey, see if the "kind" class
contains a createVKey(com.googlecode.objectify.Key) static method and if it
does, use it to construct a symmetric VKey instead of simply creating an
objectify-sided asymmetric VKey.

As a test case for this, implement the createVKey() static function for
DomainBase.  Also, create unit tests for VKeyTranslatorFactory, which
continues to house the functionality.

core/src/test/java/google/registry/model/translators/VKeyTranslatorFactoryTest.java

@@ -0,0 +1,71 @@
+// Copyright 2020 The Nomulus Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package google.registry.model.translators;
+
+import static com.google.common.truth.Truth.assertThat;
+import static google.registry.testing.DatastoreHelper.newDomainBase;
+import static google.registry.testing.DatastoreHelper.persistActiveContact;
+
+import com.googlecode.objectify.Key;
+import google.registry.model.domain.DomainBase;
+import google.registry.model.ofy.CommitLogBucket;
+import google.registry.persistence.VKey;
+import google.registry.testing.AppEngineRule;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+public class VKeyTranslatorFactoryTest {
+
+  @RegisterExtension public final AppEngineRule appEngine =
+      AppEngineRule.builder()
+          .withDatastore()
+          .build();
+
+  public VKeyTranslatorFactoryTest() {}
+
+  @Test
+  void testEntityWithVKeyCreate() {
+    // Creating an objectify key instead of a datastore key as this should get a correctly formatted
+    // key path.
+    DomainBase domain = newDomainBase("example.com", "ROID-1", persistActiveContact("contact-1"));
+    Key<DomainBase> key = Key.create(domain);
+    VKey<DomainBase> vkey = VKeyTranslatorFactory.createVKey(key);
+    assertThat(vkey.getKind()).isEqualTo(DomainBase.class);
+    assertThat(vkey.getOfyKey()).isEqualTo(key);
+    assertThat(vkey.getSqlKey()).isEqualTo("ROID-1");
+  }
+
+  @Test
+  void testEntityWithoutVKeyCreate() {
+    CommitLogBucket bucket = new CommitLogBucket.Builder().build();
+    Key<CommitLogBucket> key = Key.create(bucket);
+    VKey<CommitLogBucket> vkey = VKeyTranslatorFactory.createVKey(key);
+    assertThat(vkey.getKind()).isEqualTo(CommitLogBucket.class);
+    assertThat(vkey.getOfyKey()).isEqualTo(key);
+    assertThat(vkey.maybeGetSqlKey().isPresent()).isFalse();
+  }
+
+  @Test
+  void testUrlSafeKey() {
+    // Creating an objectify key instead of a datastore key as this should get a correctly formatted
+    // key path.
+    DomainBase domain = newDomainBase("example.com", "ROID-1", persistActiveContact("contact-1"));
+    Key<DomainBase> key = Key.create(domain);
+    VKey<DomainBase> vkey = (VKey<DomainBase>) VKeyTranslatorFactory.createVKey(key.getString());
+    assertThat(vkey.getKind()).isEqualTo(DomainBase.class);
+    assertThat(vkey.getOfyKey()).isEqualTo(key);
+    assertThat(vkey.getSqlKey()).isEqualTo("ROID-1");
+  }
+}