javatests/com/google/gerrit/server/account/externalids/ExternalIDCacheLoaderTest.java - gerrit - Git at Google

 // Copyright (C) 2019 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.server.account.externalids;

 import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;

 import com.google.common.base.CharMatcher;
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.collect.ImmutableList;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.RefNames;
 import com.google.gerrit.metrics.DisabledMetricMaker;
 import com.google.gerrit.server.account.externalids.testing.ExternalIdTestUtil;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.AllUsersNameProvider;
 import com.google.gerrit.server.config.AuthConfig;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.testing.InMemoryRepositoryManager;
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.function.Consumer;
 import java.util.stream.Stream;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.mockito.junit.MockitoJUnitRunner;

 @RunWith(MockitoJUnitRunner.class)
 public class ExternalIDCacheLoaderTest {
   private static AllUsersName ALL_USERS = new AllUsersName(AllUsersNameProvider.DEFAULT);

   private Cache<ObjectId, AllExternalIds> externalIdCache;
   private ExternalIdCacheLoader loader;
   private GitRepositoryManager repoManager = new InMemoryRepositoryManager();
   private ExternalIdReader externalIdReader;
   private ExternalIdReader externalIdReaderSpy;

   private ExternalIdFactory externalIdFactory;
   @Mock private AuthConfig authConfig;

   @Before
   public void setUp() throws Exception {
     externalIdFactory = new ExternalIdFactory(new ExternalIdKeyFactory(() -> false), authConfig);
     externalIdCache = CacheBuilder.newBuilder().build();
     repoManager.createRepository(ALL_USERS).close();
     externalIdReader =
         new ExternalIdReader(
             repoManager, ALL_USERS, new DisabledMetricMaker(), externalIdFactory, authConfig);
     externalIdReaderSpy = Mockito.spy(externalIdReader);
     loader = createLoader();
   }

   @Test
   public void worksOnSingleCommit() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     assertThat(loader.load(firstState)).isEqualTo(allFromGit(firstState));
     verify(externalIdReaderSpy, times(1)).all(firstState);
   }

   @Test
   public void reloadsSingleUpdateUsingPartialReload() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     ObjectId head = insertExternalId(2, 2);
     externalIdCache.put(firstState, allFromGit(firstState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void loadCacheSuccessfullyWhenInInconsistentState() throws Exception {
     int key = 1;
     int account = 1;
     ExternalId externalId = externalId(key, account);
     ExternalId.Key externalIdKey = externalId.key();

     Repository repo = repoManager.openRepository(ALL_USERS);
     ObjectId newState = insertExternalId(key, account);
     TreeWalk tw = new TreeWalk(repo);
     tw.reset(new RevWalk(repo).parseCommit(newState).getTree());
     tw.next();

     HashMap<ObjectId, ObjectId> additions = new HashMap<>();
     additions.put(fileNameToObjectId(tw.getPathString()), tw.getObjectId(0));
     AllExternalIds oldExternalIds =
         AllExternalIds.create(Stream.<ExternalId>builder().add(externalId).build());

     AllExternalIds allExternalIds =
         loader.buildAllExternalIds(repo, oldExternalIds, additions, new HashSet<>());

     assertThat(allExternalIds).isNotNull();
     assertThat(allExternalIds.byKey().containsKey(externalIdKey)).isTrue();
     assertThat(allExternalIds.byKey().get(externalIdKey)).isEqualTo(externalId);
   }

   private static ObjectId fileNameToObjectId(String path) {
     return ObjectId.fromString(CharMatcher.is('/').removeFrom(path));
   }

   @Test
   public void reloadsMultipleUpdatesUsingPartialReload() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     insertExternalId(2, 2);
     insertExternalId(3, 3);
     ObjectId head = insertExternalId(4, 4);
     externalIdCache.put(firstState, allFromGit(firstState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void reloadsAllExternalIdsWhenNoOldStateIsCached() throws Exception {
     insertExternalId(1, 1);
     ObjectId head = insertExternalId(2, 2);

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).all(head);
   }

   @Test
   public void fallsBackToFullReloadOnManyUpdatesOnBranch() throws Exception {
     insertExternalId(1, 1);
     ObjectId head = null;
     for (int i = 2; i < 20; i++) {
       head = insertExternalId(i, i);
     }

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).all(head);
   }

   @Test
   public void doesFullReloadWhenNoCacheStateIsFound() throws Exception {
     ObjectId head = insertExternalId(1, 1);

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).all(head);
   }

   @Test
   public void handlesDeletionInPartialReload() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     ObjectId head = deleteExternalId(1, 1);
     assertThat(allFromGit(head).byAccount().size()).isEqualTo(0);
     externalIdCache.put(firstState, allFromGit(firstState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void handlesModifyInPartialReload() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     ObjectId head =
         modifyExternalId(
             externalId(1, 1),
             externalIdFactory.create(
                 "fooschema", "bar1", Account.id(1), "foo@bar.com", "password"));
     assertThat(allFromGit(head).byAccount().size()).isEqualTo(1);
     externalIdCache.put(firstState, allFromGit(firstState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void ignoresInvalidExternalId() throws Exception {
     ObjectId firstState = insertExternalId(1, 1);
     ObjectId head;
     try (Repository repo = repoManager.openRepository(ALL_USERS);
         RevWalk rw = new RevWalk(repo)) {
       ExternalIdTestUtil.insertExternalIdWithKeyThatDoesntMatchNoteId(
           repo, rw, new PersonIdent("foo", "foo@bar.com"), Account.id(2), "test");
       head = repo.exactRef(RefNames.REFS_EXTERNAL_IDS).getObjectId();
     }

     externalIdCache.put(firstState, allFromGit(firstState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void handlesTreePrefixesInDifferentialReload() throws Exception {
     // Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
     // created a situation where NoteNames are sharded.
     ObjectId oldState = insertExternalIds(257);
     assertAllFilesHaveSlashesInPath();
     ObjectId head = insertExternalId(500, 500);
     externalIdCache.put(oldState, allFromGit(oldState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   @Test
   public void handlesReshard() throws Exception {
     // Create 256 notes (NoteMap's current sharding limit) and check that we are not yet sharding
     ObjectId oldState = insertExternalIds(256);
     assertNoFilesHaveSlashesInPath();
     // Create one more external ID and then have the Loader compute the new state
     ObjectId head = insertExternalId(500, 500);
     assertAllFilesHaveSlashesInPath(); // NoteMap resharded
     externalIdCache.put(oldState, allFromGit(oldState));

     assertThat(loader.load(head)).isEqualTo(allFromGit(head));
     verify(externalIdReaderSpy, times(1)).checkReadEnabled();
     verifyNoMoreInteractions(externalIdReaderSpy);
   }

   private ExternalIdCacheLoader createLoader() {
     return new ExternalIdCacheLoader(
         repoManager,
         ALL_USERS,
         externalIdReaderSpy,
         externalIdCache,
         new DisabledMetricMaker(),
         new Config(),
         externalIdFactory);
   }

   private AllExternalIds allFromGit(ObjectId revision) throws Exception {
     return AllExternalIds.create(externalIdReader.all(revision).stream());
   }

   private ObjectId insertExternalIds(int numberOfIdsToInsert) throws Exception {
     ObjectId oldState = null;
     // Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
     // created a situation where NoteNames are sharded.
     for (int i = 0; i < numberOfIdsToInsert; i++) {
       oldState = insertExternalId(i, i);
     }
     return oldState;
   }

   private ObjectId insertExternalId(int key, int accountId) throws Exception {
     return performExternalIdUpdate(
         u -> {
           try {
             u.insert(externalId(key, accountId));
           } catch (IOException e) {
             throw new RuntimeException(e);
           }
         });
   }

   private ObjectId modifyExternalId(ExternalId oldId, ExternalId newId) throws Exception {
     return performExternalIdUpdate(
         u -> {
           try {
             u.replace(oldId, newId);
           } catch (IOException e) {
             throw new RuntimeException(e);
           }
         });
   }

   private ObjectId deleteExternalId(int key, int accountId) throws Exception {
     return performExternalIdUpdate(u -> u.delete(externalId(key, accountId)));
   }

   private ExternalId externalId(int key, int accountId) {
     return externalIdFactory.create("fooschema", "bar" + key, Account.id(accountId));
   }

   private ObjectId performExternalIdUpdate(Consumer<ExternalIdNotes> update) throws Exception {
     try (Repository repo = repoManager.openRepository(ALL_USERS)) {
       PersonIdent updater = new PersonIdent("Foo bar", "foo@bar.com");
       ExternalIdNotes extIdNotes = ExternalIdNotes.load(ALL_USERS, repo, externalIdFactory, false);
       update.accept(extIdNotes);
       try (MetaDataUpdate metaDataUpdate =
           new MetaDataUpdate(GitReferenceUpdated.DISABLED, null, repo)) {
         metaDataUpdate.getCommitBuilder().setAuthor(updater);
         metaDataUpdate.getCommitBuilder().setCommitter(updater);
         return extIdNotes.commit(metaDataUpdate).getId();
       }
     }
   }

   private void assertAllFilesHaveSlashesInPath() throws Exception {
     assertThat(allFilesInExternalIdRef().stream().allMatch(f -> f.contains("/"))).isTrue();
   }

   private void assertNoFilesHaveSlashesInPath() throws Exception {
     assertThat(allFilesInExternalIdRef().stream().noneMatch(f -> f.contains("/"))).isTrue();
   }

   private ImmutableList<String> allFilesInExternalIdRef() throws Exception {
     try (Repository repo = repoManager.openRepository(ALL_USERS);
         TreeWalk treeWalk = new TreeWalk(repo);
         RevWalk rw = new RevWalk(repo)) {
       treeWalk.reset(
           rw.parseCommit(repo.exactRef(RefNames.REFS_EXTERNAL_IDS).getObjectId()).getTree());
       treeWalk.setRecursive(true);
       ImmutableList.Builder<String> allPaths = ImmutableList.builder();
       while (treeWalk.next()) {
         allPaths.add(treeWalk.getPathString());
       }
       return allPaths.build();
     }
   }
 }
	// Copyright (C) 2019 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.server.account.externalids;

	import static com.google.common.truth.Truth.assertThat;
	import static org.mockito.Mockito.times;
	import static org.mockito.Mockito.verify;
	import static org.mockito.Mockito.verifyNoMoreInteractions;

	import com.google.common.base.CharMatcher;
	import com.google.common.cache.Cache;
	import com.google.common.cache.CacheBuilder;
	import com.google.common.collect.ImmutableList;
	import com.google.gerrit.entities.Account;
	import com.google.gerrit.entities.RefNames;
	import com.google.gerrit.metrics.DisabledMetricMaker;
	import com.google.gerrit.server.account.externalids.testing.ExternalIdTestUtil;
	import com.google.gerrit.server.config.AllUsersName;
	import com.google.gerrit.server.config.AllUsersNameProvider;
	import com.google.gerrit.server.config.AuthConfig;
	import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
	import com.google.gerrit.server.git.GitRepositoryManager;
	import com.google.gerrit.server.git.meta.MetaDataUpdate;
	import com.google.gerrit.testing.InMemoryRepositoryManager;
	import java.io.IOException;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.function.Consumer;
	import java.util.stream.Stream;
	import org.eclipse.jgit.lib.Config;
	import org.eclipse.jgit.lib.ObjectId;
	import org.eclipse.jgit.lib.PersonIdent;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.revwalk.RevWalk;
	import org.eclipse.jgit.treewalk.TreeWalk;
	import org.junit.Before;
	import org.junit.Test;
	import org.junit.runner.RunWith;
	import org.mockito.Mock;
	import org.mockito.Mockito;
	import org.mockito.junit.MockitoJUnitRunner;

	@RunWith(MockitoJUnitRunner.class)
	public class ExternalIDCacheLoaderTest {
	private static AllUsersName ALL_USERS = new AllUsersName(AllUsersNameProvider.DEFAULT);

	private Cache<ObjectId, AllExternalIds> externalIdCache;
	private ExternalIdCacheLoader loader;
	private GitRepositoryManager repoManager = new InMemoryRepositoryManager();
	private ExternalIdReader externalIdReader;
	private ExternalIdReader externalIdReaderSpy;

	private ExternalIdFactory externalIdFactory;
	@Mock private AuthConfig authConfig;

	@Before
	public void setUp() throws Exception {
	externalIdFactory = new ExternalIdFactory(new ExternalIdKeyFactory(() -> false), authConfig);
	externalIdCache = CacheBuilder.newBuilder().build();
	repoManager.createRepository(ALL_USERS).close();
	externalIdReader =
	new ExternalIdReader(
	repoManager, ALL_USERS, new DisabledMetricMaker(), externalIdFactory, authConfig);
	externalIdReaderSpy = Mockito.spy(externalIdReader);
	loader = createLoader();
	}

	@Test
	public void worksOnSingleCommit() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	assertThat(loader.load(firstState)).isEqualTo(allFromGit(firstState));
	verify(externalIdReaderSpy, times(1)).all(firstState);
	}

	@Test
	public void reloadsSingleUpdateUsingPartialReload() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	ObjectId head = insertExternalId(2, 2);
	externalIdCache.put(firstState, allFromGit(firstState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void loadCacheSuccessfullyWhenInInconsistentState() throws Exception {
	int key = 1;
	int account = 1;
	ExternalId externalId = externalId(key, account);
	ExternalId.Key externalIdKey = externalId.key();

	Repository repo = repoManager.openRepository(ALL_USERS);
	ObjectId newState = insertExternalId(key, account);
	TreeWalk tw = new TreeWalk(repo);
	tw.reset(new RevWalk(repo).parseCommit(newState).getTree());
	tw.next();

	HashMap<ObjectId, ObjectId> additions = new HashMap<>();
	additions.put(fileNameToObjectId(tw.getPathString()), tw.getObjectId(0));
	AllExternalIds oldExternalIds =
	AllExternalIds.create(Stream.<ExternalId>builder().add(externalId).build());

	AllExternalIds allExternalIds =
	loader.buildAllExternalIds(repo, oldExternalIds, additions, new HashSet<>());

	assertThat(allExternalIds).isNotNull();
	assertThat(allExternalIds.byKey().containsKey(externalIdKey)).isTrue();
	assertThat(allExternalIds.byKey().get(externalIdKey)).isEqualTo(externalId);
	}

	private static ObjectId fileNameToObjectId(String path) {
	return ObjectId.fromString(CharMatcher.is('/').removeFrom(path));
	}

	@Test
	public void reloadsMultipleUpdatesUsingPartialReload() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	insertExternalId(2, 2);
	insertExternalId(3, 3);
	ObjectId head = insertExternalId(4, 4);
	externalIdCache.put(firstState, allFromGit(firstState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void reloadsAllExternalIdsWhenNoOldStateIsCached() throws Exception {
	insertExternalId(1, 1);
	ObjectId head = insertExternalId(2, 2);

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).all(head);
	}

	@Test
	public void fallsBackToFullReloadOnManyUpdatesOnBranch() throws Exception {
	insertExternalId(1, 1);
	ObjectId head = null;
	for (int i = 2; i < 20; i++) {
	head = insertExternalId(i, i);
	}

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).all(head);
	}

	@Test
	public void doesFullReloadWhenNoCacheStateIsFound() throws Exception {
	ObjectId head = insertExternalId(1, 1);

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).all(head);
	}

	@Test
	public void handlesDeletionInPartialReload() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	ObjectId head = deleteExternalId(1, 1);
	assertThat(allFromGit(head).byAccount().size()).isEqualTo(0);
	externalIdCache.put(firstState, allFromGit(firstState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void handlesModifyInPartialReload() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	ObjectId head =
	modifyExternalId(
	externalId(1, 1),
	externalIdFactory.create(
	"fooschema", "bar1", Account.id(1), "foo@bar.com", "password"));
	assertThat(allFromGit(head).byAccount().size()).isEqualTo(1);
	externalIdCache.put(firstState, allFromGit(firstState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void ignoresInvalidExternalId() throws Exception {
	ObjectId firstState = insertExternalId(1, 1);
	ObjectId head;
	try (Repository repo = repoManager.openRepository(ALL_USERS);
	RevWalk rw = new RevWalk(repo)) {
	ExternalIdTestUtil.insertExternalIdWithKeyThatDoesntMatchNoteId(
	repo, rw, new PersonIdent("foo", "foo@bar.com"), Account.id(2), "test");
	head = repo.exactRef(RefNames.REFS_EXTERNAL_IDS).getObjectId();
	}

	externalIdCache.put(firstState, allFromGit(firstState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void handlesTreePrefixesInDifferentialReload() throws Exception {
	// Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
	// created a situation where NoteNames are sharded.
	ObjectId oldState = insertExternalIds(257);
	assertAllFilesHaveSlashesInPath();
	ObjectId head = insertExternalId(500, 500);
	externalIdCache.put(oldState, allFromGit(oldState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	@Test
	public void handlesReshard() throws Exception {
	// Create 256 notes (NoteMap's current sharding limit) and check that we are not yet sharding
	ObjectId oldState = insertExternalIds(256);
	assertNoFilesHaveSlashesInPath();
	// Create one more external ID and then have the Loader compute the new state
	ObjectId head = insertExternalId(500, 500);
	assertAllFilesHaveSlashesInPath(); // NoteMap resharded
	externalIdCache.put(oldState, allFromGit(oldState));

	assertThat(loader.load(head)).isEqualTo(allFromGit(head));
	verify(externalIdReaderSpy, times(1)).checkReadEnabled();
	verifyNoMoreInteractions(externalIdReaderSpy);
	}

	private ExternalIdCacheLoader createLoader() {
	return new ExternalIdCacheLoader(
	repoManager,
	ALL_USERS,
	externalIdReaderSpy,
	externalIdCache,
	new DisabledMetricMaker(),
	new Config(),
	externalIdFactory);
	}

	private AllExternalIds allFromGit(ObjectId revision) throws Exception {
	return AllExternalIds.create(externalIdReader.all(revision).stream());
	}

	private ObjectId insertExternalIds(int numberOfIdsToInsert) throws Exception {
	ObjectId oldState = null;
	// Create more than 256 notes (NoteMap's current sharding limit) and check that we really have
	// created a situation where NoteNames are sharded.
	for (int i = 0; i < numberOfIdsToInsert; i++) {
	oldState = insertExternalId(i, i);
	}
	return oldState;
	}

	private ObjectId insertExternalId(int key, int accountId) throws Exception {
	return performExternalIdUpdate(
	u -> {
	try {
	u.insert(externalId(key, accountId));
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	});
	}

	private ObjectId modifyExternalId(ExternalId oldId, ExternalId newId) throws Exception {
	return performExternalIdUpdate(
	u -> {
	try {
	u.replace(oldId, newId);
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	});
	}

	private ObjectId deleteExternalId(int key, int accountId) throws Exception {
	return performExternalIdUpdate(u -> u.delete(externalId(key, accountId)));
	}

	private ExternalId externalId(int key, int accountId) {
	return externalIdFactory.create("fooschema", "bar" + key, Account.id(accountId));
	}

	private ObjectId performExternalIdUpdate(Consumer<ExternalIdNotes> update) throws Exception {
	try (Repository repo = repoManager.openRepository(ALL_USERS)) {
	PersonIdent updater = new PersonIdent("Foo bar", "foo@bar.com");
	ExternalIdNotes extIdNotes = ExternalIdNotes.load(ALL_USERS, repo, externalIdFactory, false);
	update.accept(extIdNotes);
	try (MetaDataUpdate metaDataUpdate =
	new MetaDataUpdate(GitReferenceUpdated.DISABLED, null, repo)) {
	metaDataUpdate.getCommitBuilder().setAuthor(updater);
	metaDataUpdate.getCommitBuilder().setCommitter(updater);
	return extIdNotes.commit(metaDataUpdate).getId();
	}
	}
	}

	private void assertAllFilesHaveSlashesInPath() throws Exception {
	assertThat(allFilesInExternalIdRef().stream().allMatch(f -> f.contains("/"))).isTrue();
	}

	private void assertNoFilesHaveSlashesInPath() throws Exception {
	assertThat(allFilesInExternalIdRef().stream().noneMatch(f -> f.contains("/"))).isTrue();
	}

	private ImmutableList<String> allFilesInExternalIdRef() throws Exception {
	try (Repository repo = repoManager.openRepository(ALL_USERS);
	TreeWalk treeWalk = new TreeWalk(repo);
	RevWalk rw = new RevWalk(repo)) {
	treeWalk.reset(
	rw.parseCommit(repo.exactRef(RefNames.REFS_EXTERNAL_IDS).getObjectId()).getTree());
	treeWalk.setRecursive(true);
	ImmutableList.Builder<String> allPaths = ImmutableList.builder();
	while (treeWalk.next()) {
	allPaths.add(treeWalk.getPathString());
	}
	return allPaths.build();
	}
	}
	}