Start implementing OnlineNoteDbMigrationIT

This still requires @Sandboxed, since we want each test to start from
scratch with ReviewDb, but using an in-memory implementation and only
spawning the Daemon once will still be much faster and easier to code
than the test of the standalone MigrateToNoteDb program.

Rename MigrateToNoteDbIT to OfflineNoteDbMigrationIT to make the
contrast clear.

Change-Id: I565273afab02332ca9492648607c2e6ad0291b76

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/pgm/OfflineNoteDbMigrationIT.java

@@ -60,9 +60,16 @@ import org.junit.Test;
 import org.junit.rules.TestWatcher;
 import org.junit.runner.Description;
 
+/**
+ * Tests for offline {@code migrate-to-note-db} program.
+ *
+ * <p><strong>Note:</strong> These tests are very slow due to the repeated daemon startup. Prefer
+ * adding tests to {@link com.google.gerrit.acceptance.server.notedb.OnlineNoteDbMigrationIT} if
+ * possible.
+ */
 @UseLocalDisk
 @NoHttpd
-public class MigrateToNoteDbIT {
+public class OfflineNoteDbMigrationIT {
   @Rule
   public TestWatcher testWatcher =
       new TestWatcher() {

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/server/notedb/OnlineNoteDbMigrationIT.java

@@ -0,0 +1,82 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// 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 com.google.gerrit.acceptance.server.notedb;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth8.assertThat;
+import static com.google.common.truth.TruthJUnit.assume;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.NoHttpd;
+import com.google.gerrit.acceptance.PushOneCommit;
+import com.google.gerrit.acceptance.Sandboxed;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.reviewdb.server.ReviewDbUtil;
+import com.google.gerrit.server.notedb.NoteDbChangeState;
+import com.google.gerrit.server.notedb.NoteDbChangeState.PrimaryStorage;
+import com.google.gerrit.server.notedb.NoteDbChangeState.RefState;
+import com.google.gerrit.server.notedb.NotesMigrationState;
+import com.google.gerrit.server.notedb.rebuild.NoteDbMigrator;
+import com.google.gerrit.testutil.NoteDbMode;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.junit.Before;
+import org.junit.Test;
+
+@Sandboxed
+@NoHttpd
+public class OnlineNoteDbMigrationIT extends AbstractDaemonTest {
+  @Inject private Provider<NoteDbMigrator.Builder> migratorBuilderProvider;
+
+  @Before
+  public void setUp() {
+    assume().that(NoteDbMode.get()).isEqualTo(NoteDbMode.OFF);
+    assertNotesMigrationState(NotesMigrationState.REVIEW_DB);
+  }
+
+  @Test
+  public void rebuildOneChangeTrialMode() throws Exception {
+    PushOneCommit.Result r = createChange();
+    Change.Id id = r.getChange().getId();
+
+    try (NoteDbMigrator migrator = migratorBuilderProvider.get().setTrialMode(true).build()) {
+      migrator.migrate();
+    }
+    assertNotesMigrationState(NotesMigrationState.READ_WRITE_NO_SEQUENCE);
+
+    ObjectId metaId;
+    try (Repository repo = repoManager.openRepository(project)) {
+      Ref ref = repo.exactRef(RefNames.changeMetaRef(id));
+      assertThat(ref).isNotNull();
+      metaId = ref.getObjectId();
+    }
+
+    Change c = ReviewDbUtil.unwrapDb(db).changes().get(id);
+    assertThat(c).isNotNull();
+    NoteDbChangeState state = NoteDbChangeState.parse(c);
+    assertThat(state).isNotNull();
+    assertThat(state.getPrimaryStorage()).isEqualTo(PrimaryStorage.REVIEW_DB);
+    assertThat(state.getRefState()).hasValue(RefState.create(metaId, ImmutableMap.of()));
+  }
+
+  private void assertNotesMigrationState(NotesMigrationState expected) {
+    assertThat(NotesMigrationState.forNotesMigration(notesMigration)).hasValue(expected);
+  }
+}