2 files changed, 24 insertions, 2 deletions
diff --git a/helpers/memenv/memenv.cc b/helpers/memenv/memenv.cc
index 43ef2e0729..9a98884daf 100644
--- a/helpers/memenv/memenv.cc
+++ b/helpers/memenv/memenv.cc
@@ -277,6 +277,19 @@ class InMemoryEnv : public EnvWrapper {
     return Status::OK();
   }
 
+  virtual Status NewAppendableFile(const std::string& fname,
+                                   WritableFile** result) {
+    MutexLock lock(&mutex_);
+    FileState** sptr = &file_map_[fname];
+    FileState* file = *sptr;
+    if (file == NULL) {
+      file = new FileState();
+      file->Ref();
+    }
+    *result = new WritableFileImpl(file);
+    return Status::OK();
+  }
+
   virtual bool FileExists(const std::string& fname) {
     MutexLock lock(&mutex_);
     return file_map_.find(fname) != file_map_.end();
diff --git a/helpers/memenv/memenv_test.cc b/helpers/memenv/memenv_test.cc
index a44310fed8..5cff77613f 100644
--- a/helpers/memenv/memenv_test.cc
+++ b/helpers/memenv/memenv_test.cc
@@ -40,6 +40,8 @@ TEST(MemEnvTest, Basics) {
 
   // Create a file.
   ASSERT_OK(env_->NewWritableFile("/dir/f", &writable_file));
+  ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
+  ASSERT_EQ(0, file_size);
   delete writable_file;
 
   // Check that the file exists.
@@ -55,9 +57,16 @@ TEST(MemEnvTest, Basics) {
   ASSERT_OK(writable_file->Append("abc"));
   delete writable_file;
 
-  // Check for expected size.
+  // Check that append works.
+  ASSERT_OK(env_->NewAppendableFile("/dir/f", &writable_file));
   ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
   ASSERT_EQ(3, file_size);
+  ASSERT_OK(writable_file->Append("hello"));
+  delete writable_file;
+
+  // Check for expected size.
+  ASSERT_OK(env_->GetFileSize("/dir/f", &file_size));
+  ASSERT_EQ(8, file_size);
 
   // Check that renaming works.
   ASSERT_TRUE(!env_->RenameFile("/dir/non_existent", "/dir/g").ok());
@@ -65,7 +74,7 @@ TEST(MemEnvTest, Basics) {
   ASSERT_TRUE(!env_->FileExists("/dir/f"));
   ASSERT_TRUE(env_->FileExists("/dir/g"));
   ASSERT_OK(env_->GetFileSize("/dir/g", &file_size));
-  ASSERT_EQ(3, file_size);
+  ASSERT_EQ(8, file_size);
 
   // Check that opening non-existent file fails.
   SequentialFile* seq_file;