Allow TreeCreator to work with an emtpy tree as base

Most tree modifications won't do anything when presented with an empty tree. Currently, only ChangeFileContentModification has reasonable behavior for it. Use case for this: A TreeCreator with an empty tree and some ChangeFileContentModification can be used to easily construct a tree with some desired content. Change-Id: Ib7de3acaa91a60ad454175f4baccd847dd4b2386
2020-07-30 16:24:35 +02:00
parent 60e872dd5c
commit d18582477e
8 changed files with 163 additions and 27 deletions
--- a/javatests/com/google/gerrit/server/edit/tree/TreeCreatorTest.java
+++ b/javatests/com/google/gerrit/server/edit/tree/TreeCreatorTest.java
@@ -0,0 +1,110 @@
+// Copyright (C) 2020 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.edit.tree;
+
+import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.common.RawInputUtil;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
+import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectReader;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevObject;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+public class TreeCreatorTest {
+
+  private Repository repository;
+  private TestRepository<?> testRepository;
+
+  @Before
+  public void setUp() throws Exception {
+    repository = new InMemoryRepository(new DfsRepositoryDescription("Test Repository"));
+    testRepository = new TestRepository<>(repository);
+  }
+
+  @After
+  public void tearDown() throws Exception {
+    if (testRepository != null) {
+      testRepository.close();
+    }
+  }
+
+  @Test
+  public void fileContentModificationWorksWithEmptyTree() throws Exception {
+    TreeCreator treeCreator = TreeCreator.basedOnEmptyTree();
+    treeCreator.addTreeModifications(
+        ImmutableList.of(
+            new ChangeFileContentModification("file.txt", RawInputUtil.create("Line 1"))));
+    ObjectId newTreeId = treeCreator.createNewTreeAndGetId(repository);
+
+    String fileContent = getFileContent(newTreeId, "file.txt");
+    assertThat(fileContent).isEqualTo("Line 1");
+  }
+
+  @Test
+  public void renameFileModificationDoesNotComplainAboutEmptyTree() throws Exception {
+    TreeCreator treeCreator = TreeCreator.basedOnEmptyTree();
+    treeCreator.addTreeModifications(
+        ImmutableList.of(new RenameFileModification("oldfileName", "newFileName")));
+    ObjectId newTreeId = treeCreator.createNewTreeAndGetId(repository);
+
+    assertThat(isEmptyTree(newTreeId)).isTrue();
+  }
+
+  @Test
+  public void deleteFileModificationDoesNotComplainAboutEmptyTree() throws Exception {
+    TreeCreator treeCreator = TreeCreator.basedOnEmptyTree();
+    treeCreator.addTreeModifications(ImmutableList.of(new DeleteFileModification("file.txt")));
+    ObjectId newTreeId = treeCreator.createNewTreeAndGetId(repository);
+
+    assertThat(isEmptyTree(newTreeId)).isTrue();
+  }
+
+  @Test
+  public void restoreFileModificationDoesNotComplainAboutEmptyTree() throws Exception {
+    TreeCreator treeCreator = TreeCreator.basedOnEmptyTree();
+    treeCreator.addTreeModifications(ImmutableList.of(new RestoreFileModification("file.txt")));
+    ObjectId newTreeId = treeCreator.createNewTreeAndGetId(repository);
+
+    assertThat(isEmptyTree(newTreeId)).isTrue();
+  }
+
+  private String getFileContent(ObjectId treeId, String filePath) throws Exception {
+    try (RevWalk revWalk = new RevWalk(repository);
+        ObjectReader reader = revWalk.getObjectReader()) {
+      RevTree revTree = revWalk.parseTree(treeId);
+      RevObject revObject = testRepository.get(revTree, filePath);
+      return new String(reader.open(revObject, OBJ_BLOB).getBytes(), UTF_8);
+    }
+  }
+
+  private boolean isEmptyTree(ObjectId treeId) throws Exception {
+    try (TreeWalk treeWalk = new TreeWalk(repository)) {
+      treeWalk.reset(treeId);
+      return !treeWalk.next();
+    }
+  }
+}