diff --git a/CMakeLists.txt b/CMakeLists.txt
index 31b42d272652fc3405008585d32cea18e5a1403a..e0caaeb6cc52d914648f1c6f2acc48a196d447c8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,6 +26,7 @@ project(libcaosdb_inttests
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 
 # dependency management with conan
diff --git a/README.md b/README.md
index 551117a3b4eb123829e43fb3cefc15d04d8fc19c..9d2b880004b551f8e32eb0254e47377744584e69 100644
--- a/README.md
+++ b/README.md
@@ -12,11 +12,17 @@ Integration tests for caosdb-cpplib and the caosdb-server
 
 # Run tests
 
+## Prerequisite
+Create a local conan package from the caosdb-cpplib repository
+
+## Build & Execution
 1. `mkdir build && cd build/`
 2. `conan install .. -s "compiler.libcxx=libstdc++11"`
 3. `cmake -B . ..`
 4. `cmake --build .`
 5. Setup env vars
+	- CAOSDB_SERVER_GRPC_PORT_HTTP
+	- CAOSDB_SERVER_HOST
+	- CAOSDB_SERVER_GRPC_PORT_HTTPS
+	- CAOSDB_SERVER_CERT
 6. Run with `ctest` in the build directory.
-
-
diff --git a/conanfile.txt b/conanfile.txt
index a5a7c5f57a87bc692b51558e8483daa28aeb79e6..ccd05f44e4855c4d4b13dc1fbc7df8554dd4e8ad 100644
--- a/conanfile.txt
+++ b/conanfile.txt
@@ -1,5 +1,5 @@
 [requires]
-caosdb/0.0.10
+caosdb/0.0.11
 gtest/1.11.0
 
 [generators]
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index d1a13512d80b1cb8bca078f001987e958aa0e874..ecb011e99179399e62f646f3027951aff0163466 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -24,6 +24,7 @@
 set(test_cases
     test_connection
     test_transaction
+	#test_file_transmission TODO add once fixed
     test_ccaosdb
     )
 
@@ -82,7 +83,7 @@ if(LINTING)
             "--warnings-as-errors=*"
             "--fix")
         set(_CMAKE_CXX_CLANG_TIDY_CHECKS
-          "--checks=*,-fuchsia-*,-llvmlibc-*,-cert-err58-cpp,-cppcoreguidelines-avoid-non-const-global-variables,-cppcoreguidelines-owning-memory,-modernize-use-trailing-return-type,-google-readability-avoid-underscore-in-googletest-name,-cppcoreguidelines-avoid-magic-numbers,-readability-magic-numbers,-cppcoreguidelines-avoid-goto,-hicpp-avoid-goto,-readability-function-cognitive-complexity")
+          "--checks=*,-fuchsia-*,-llvmlibc-*,-cert-err58-cpp,-cppcoreguidelines-avoid-non-const-global-variables,-cppcoreguidelines-owning-memory,-modernize-use-trailing-return-type,-google-readability-avoid-underscore-in-googletest-name,-cppcoreguidelines-avoid-magic-numbers,-readability-magic-numbers,-cppcoreguidelines-avoid-goto,-hicpp-avoid-goto,-readability-function-cognitive-complexity,-cppcoreguidelines-non-private-member-variables-in-classes,-misc-non-private-member-variables-in-classes,-cppcoreguidelines-pro-type-vararg,-cppcoreguidelines-pro-bounds-array-to-pointer-decay,-hicpp-no-array-decay")
     endif()
 else()
     message(STATUS "LINTING is OFF")
@@ -105,7 +106,8 @@ foreach (i RANGE "${len_test_cases}")
     target_link_libraries(${test_case_name} PRIVATE ${CONAN_LIBS_CAOSDB}
         ${CONAN_LIBS_GTEST} ${CONAN_LIBS_GRPC} ${CONAN_LIBS_ABSEIL}
         ${CONAN_LIBS_OPENSSL} ${CONAN_LIBS_C-ARES} ${CONAN_LIBS_BZIP2}
-        ${CONAN_LIBS_PROTOBUF} ${CONAN_LIBS_ZLIB} ${CONAN_LIBS_RE2})
+        ${CONAN_LIBS_PROTOBUF} ${CONAN_LIBS_ZLIB} ${CONAN_LIBS_RE2}
+        ${CONAN_LIBS_BOOST})
     target_include_directories(${test_case_name}
         PUBLIC ${CONAN_INCLUDE_DIRS} ${CMAKE_CURRENT_SOURCE_DIR})
     if(LINTING)
diff --git a/test/caosdb_test_utility.h b/test/caosdb_test_utility.h
index 4c97c203a8ab55c9d239d824cd274fe3b99aa60b..4cde3dc5059acf60a04b071154b44a59b67e9833 100644
--- a/test/caosdb_test_utility.h
+++ b/test/caosdb_test_utility.h
@@ -33,16 +33,16 @@
  */
 #define EXPECT_THROW_MESSAGE(statement, exeption_type, message)                \
   EXPECT_THROW(                                                                \
-    try { statement; } catch (const exeption_type &e) {                        \
-      EXPECT_EQ(std::string(e.what()), message);                               \
-      throw;                                                                   \
-    },                                                                         \
-    exeption_type)
+      try { statement; } catch (const exeption_type &e) {                      \
+        EXPECT_EQ(std::string(e.what()), message);                             \
+        throw;                                                                 \
+      },                                                                       \
+      exeption_type)
 #define ASSERT_THROW_MESSAGE(statement, exeption_type, message)                \
   ASSERT_THROW(                                                                \
-    try { statement; } catch (const exeption_type &e) {                        \
-      ASSERT_EQ(std::string(e.what()), message);                               \
-      throw;                                                                   \
-    },                                                                         \
-    exeption_type)
+      try { statement; } catch (const exeption_type &e) {                      \
+        ASSERT_EQ(std::string(e.what()), message);                             \
+        throw;                                                                 \
+      },                                                                       \
+      exeption_type)
 #endif
diff --git a/test/test_ccaosdb.cpp b/test/test_ccaosdb.cpp
index 1bf33420edef2b62f4dbfa395ffd2b401b43ea68..f56e92d620d3a18b1ffa7262f34d139963a3987a 100644
--- a/test/test_ccaosdb.cpp
+++ b/test/test_ccaosdb.cpp
@@ -2,6 +2,7 @@
  * This file is a part of the CaosDB Project.
  *
  * Copyright (C) 2021 Timm Fitschen <t.fitschen@indiscale.com>
+ * Copyright (C) 2021 Florian Spreckelsen <f.spreckelsen@indiscale.com>
  * Copyright (C) 2021 IndiScale GmbH <info@indiscale.com>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -17,6 +18,8 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <https://www.gnu.org/licenses/>.
  */
+#include "caosdb/message_code.h"   // for MessageCode
+#include "caosdb/status_code.h"    // for StatusCode
 #include "ccaosdb.h"               // for caosdb_info_version_info, caosdb_...
 #include "gtest/gtest-message.h"   // for Message
 #include "gtest/gtest-test-part.h" // for TestPartResult
@@ -34,9 +37,182 @@ TEST(test_ccaosdb, connection_ssl_authentication_success) {
   auto major = caosdb_constants_COMPATIBLE_SERVER_VERSION_MAJOR();
   auto minor = caosdb_constants_COMPATIBLE_SERVER_VERSION_MINOR();
   const auto *const pre_release =
-    caosdb_constants_COMPATIBLE_SERVER_VERSION_PRE_RELEASE();
+      caosdb_constants_COMPATIBLE_SERVER_VERSION_PRE_RELEASE();
 
   EXPECT_EQ(major, version_info.major);
   EXPECT_EQ(minor, version_info.minor);
   EXPECT_STREQ(pre_release, version_info.pre_release);
 }
+
+TEST(test_ccaosdb, test_count_query) {
+
+  caosdb_connection_connection connection;
+  int return_code(
+    caosdb_connection_connection_manager_get_default_connection(&connection));
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_transaction transaction;
+  return_code =
+    caosdb_connection_connection_create_transaction(&connection, &transaction);
+  EXPECT_EQ(return_code, 0);
+
+  // COUNT query with an empty result
+  return_code = caosdb_transaction_transaction_query(&transaction,
+                                                     "COUNT ENTITY WITH id=-1");
+  EXPECT_EQ(return_code, caosdb::StatusCode::GO_ON);
+
+  return_code = caosdb_transaction_transaction_execute(&transaction);
+  EXPECT_EQ(return_code, 0);
+
+  long dummy(-1);       // NOLINT
+  long *count = &dummy; // NOLINT
+  return_code =
+    caosdb_transaction_transaction_get_count_result(&transaction, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 0);
+
+  return_code = caosdb_transaction_delete_transaction(&transaction);
+  EXPECT_EQ(return_code, 0);
+}
+
+TEST(test_ccaosdb, test_query) {
+  caosdb_connection_connection connection;
+  int return_code(
+    caosdb_connection_connection_manager_get_default_connection(&connection));
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_transaction transaction;
+  return_code =
+    caosdb_connection_connection_create_transaction(&connection, &transaction);
+  EXPECT_EQ(return_code, 0);
+
+  return_code = caosdb_transaction_transaction_query(&transaction,
+                                                     "FIND ENTITY WITH id=-1");
+  EXPECT_EQ(return_code, caosdb::StatusCode::GO_ON);
+
+  return_code = caosdb_transaction_transaction_execute(&transaction);
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_result_set result_set;
+  return_code =
+    caosdb_transaction_transaction_get_result_set(&transaction, &result_set);
+  EXPECT_EQ(return_code, 0);
+
+  int dummy(-1);
+  int *count = &dummy; // NOLINT
+  return_code = caosdb_transaction_result_set_size(&result_set, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 0);
+
+  return_code = caosdb_transaction_delete_transaction(&transaction);
+  EXPECT_EQ(return_code, 0);
+}
+
+TEST(test_ccaosdb, test_single_id_retrieve) {
+  caosdb_connection_connection connection;
+  int return_code(
+    caosdb_connection_connection_manager_get_default_connection(&connection));
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_transaction transaction;
+  return_code =
+    caosdb_connection_connection_create_transaction(&connection, &transaction);
+  EXPECT_EQ(return_code, 0);
+
+  return_code =
+    caosdb_transaction_transaction_retrieve_by_id(&transaction, "21");
+  EXPECT_EQ(return_code, caosdb::StatusCode::GO_ON);
+
+  return_code = caosdb_transaction_transaction_execute(&transaction);
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_result_set result_set;
+  return_code =
+    caosdb_transaction_transaction_get_result_set(&transaction, &result_set);
+  EXPECT_EQ(return_code, 0);
+
+  int dummy(-1);
+  int *count = &dummy; // NOLINT
+  return_code = caosdb_transaction_result_set_size(&result_set, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 1);
+
+  caosdb_entity_entity entity;
+  return_code = caosdb_transaction_result_set_at(&result_set, &entity, 0);
+  EXPECT_EQ(return_code, 0);
+
+  return_code = caosdb_entity_entity_get_errors_size(&entity, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 0);
+
+  char out[255] = {"255"}; // NOLINT
+  return_code = caosdb_entity_entity_get_name(&entity, out);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_STREQ(out, "unit");
+
+  return_code = caosdb_transaction_delete_transaction(&transaction);
+  EXPECT_EQ(return_code, 0);
+}
+
+TEST(test_ccaosdb, test_multi_id_retrieve) {
+  caosdb_connection_connection connection;
+  int return_code(
+    caosdb_connection_connection_manager_get_default_connection(&connection));
+  EXPECT_EQ(return_code, 0);
+
+  caosdb_transaction_transaction transaction;
+  return_code =
+    caosdb_connection_connection_create_transaction(&connection, &transaction);
+  EXPECT_EQ(return_code, 0);
+
+  const char *ids[] = {"20", "21", "22"}; // NOLINT
+  return_code =
+    caosdb_transaction_transaction_retrieve_by_ids(&transaction, ids, 3);
+  EXPECT_EQ(return_code, caosdb::StatusCode::GO_ON);
+
+  return_code = caosdb_transaction_transaction_execute(&transaction);
+  // Should have an error since entity 22 doesn't exist
+  EXPECT_TRUE((return_code > 0));
+
+  caosdb_transaction_result_set result_set;
+  return_code =
+    caosdb_transaction_transaction_get_result_set(&transaction, &result_set);
+  EXPECT_EQ(return_code, 0);
+
+  int dummy(-1);
+  int *count = &dummy; // NOLINT
+  return_code = caosdb_transaction_result_set_size(&result_set, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 3);
+
+  caosdb_entity_entity entity;
+  return_code = caosdb_transaction_result_set_at(&result_set, &entity, 1);
+  EXPECT_EQ(return_code, 0);
+
+  return_code = caosdb_entity_entity_get_errors_size(&entity, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 0);
+
+  char out[255] = {"255"}; // NOLINT
+  return_code = caosdb_entity_entity_get_name(&entity, out);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_STREQ(out, "unit");
+
+  caosdb_entity_entity other_entity;
+  return_code = caosdb_transaction_result_set_at(&result_set, &other_entity, 2);
+  EXPECT_EQ(return_code, 0);
+  return_code = caosdb_entity_entity_get_errors_size(&other_entity, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, 1);
+
+  caosdb_entity_message err_msg;
+  return_code = caosdb_entity_entity_get_error(&other_entity, &err_msg, 0);
+  EXPECT_EQ(return_code, 0);
+
+  return_code = caosdb_entity_message_get_code(&err_msg, count);
+  EXPECT_EQ(return_code, 0);
+  EXPECT_EQ(*count, caosdb::entity::MessageCode::ENTITY_DOES_NOT_EXIST);
+
+  return_code = caosdb_transaction_delete_transaction(&transaction);
+  EXPECT_EQ(return_code, 0);
+}
diff --git a/test/test_connection.cpp b/test/test_connection.cpp
index ed1ca1faa5186105c87edb5068916f76ab850882..9a3f91168ed23497b700d9119bcba48af4c43e38 100644
--- a/test/test_connection.cpp
+++ b/test/test_connection.cpp
@@ -28,9 +28,9 @@
 #include "caosdb/info.h"                 // for VersionInfo
 #include "caosdb/utility.h"              // for get_env_var
 #include "caosdb_test_utility.h"         // for EXPECT_THROW_MESSAGE
-#include <gtest/gtest-message.h>         // for Message
-#include <gtest/gtest-test-part.h>       // for SuiteApiResolver, TestPartR...
-#include "gtest/gtest_pred_impl.h"       // for Test, TestInfo, TEST, EXPEC...
+#include <gtest/gtest-message.h>         // NOLINT    TODO ?? for Message
+#include <gtest/gtest-test-part.h>       // NOLINT    for SuiteApiResolver, TestPartR...
+#include "gtest/gtest_pred_impl.h"       // NOLINT    for Test, TestInfo, TEST, EXPEC...
 #include <memory>                        // for allocator, unique_ptr, __sh...
 #include <string>                        // for stoi, string
 
@@ -62,10 +62,10 @@ TEST(test_connection, connect_somehost_42347_fails) {
 
 TEST(test_connection, connection_insecure_authentication_error_anonymous) {
   const auto *port_str =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTP", "8080");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTP", "8080");
   auto port = std::stoi(port_str);
   const auto *const host =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
 
   auto config = InsecureConnectionConfiguration(host, port);
   auto connection = Connection(config);
@@ -75,12 +75,12 @@ TEST(test_connection, connection_insecure_authentication_error_anonymous) {
 
 TEST(test_connection, connection_ssl_authentication_error_anonymous) {
   const auto *port_str =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTPS", "8443");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTPS", "8443");
   auto port = std::stoi(port_str);
   const auto *const host =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
   const auto path =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_CERT", std::string());
+      caosdb::utility::get_env_var("CAOSDB_SERVER_CERT", std::string());
 
   auto cert = PemFileCertificateProvider(path);
   auto config = TlsConnectionConfiguration(host, port, cert);
@@ -94,12 +94,12 @@ TEST(test_connection, connection_ssl_authentication_error_anonymous) {
 
 TEST(test_connection, connection_ssl_authentication_error_wrong_credentials) {
   const auto *port_str =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTPS", "8443");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_GRPC_PORT_HTTPS", "8443");
   auto port = std::stoi(port_str);
   const auto *const host =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
+      caosdb::utility::get_env_var("CAOSDB_SERVER_HOST", "localhost");
   const auto path =
-    caosdb::utility::get_env_var("CAOSDB_SERVER_CERT", std::string());
+      caosdb::utility::get_env_var("CAOSDB_SERVER_CERT", std::string());
   const auto *const user = "not-a-user-23461237";
   const auto *const password = "very-c-cred";
 
@@ -109,10 +109,10 @@ TEST(test_connection, connection_ssl_authentication_error_wrong_credentials) {
   auto connection = Connection(config);
 
   EXPECT_THROW_MESSAGE(
-    connection.RetrieveVersionInfo(), AuthenticationError,
-    "The attempt to execute this transaction has not been executed at all "
-    "because the authentication did not succeed. Original error: "
-    "Authentication failed. Username or password wrong.");
+      connection.RetrieveVersionInfo(), AuthenticationError,
+      "The attempt to execute this transaction has not been executed at all "
+      "because the authentication did not succeed. Original error: "
+      "Authentication failed. Username or password wrong.");
 }
 
 TEST(test_connection, connection_ssl_authentication_success) {
@@ -121,7 +121,7 @@ TEST(test_connection, connection_ssl_authentication_success) {
   auto major = caosdb::COMPATIBLE_SERVER_VERSION_MAJOR;
   auto minor = caosdb::COMPATIBLE_SERVER_VERSION_MINOR;
   const auto pre_release =
-    std::string(caosdb::COMPATIBLE_SERVER_VERSION_PRE_RELEASE);
+      std::string(caosdb::COMPATIBLE_SERVER_VERSION_PRE_RELEASE);
 
   const auto &v_info = connection->RetrieveVersionInfo();
   EXPECT_EQ(major, v_info.GetMajor());
diff --git a/test/test_file_transmission.cpp b/test/test_file_transmission.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..eab5b785fcd15510b7aebce0d8a72bc78fb05fff
--- /dev/null
+++ b/test/test_file_transmission.cpp
@@ -0,0 +1,164 @@
+/*
+ * This file is a part of the CaosDB Project.
+ *
+ * Copyright (C) 2021 Timm Fitschen <t.fitschen@indiscale.com>
+ * Copyright (C) 2021 IndiScale GmbH <info@indiscale.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#include "caosdb/connection.h" // for Connection, ConnectionManager
+#include "caosdb/entity.h"
+#include "caosdb/entity/v1alpha1/main.pb.h"
+#include "caosdb/transaction.h"    // for Transaction, UniqueRe...
+#include "gtest/gtest-message.h"   // for Message
+#include "gtest/gtest-test-part.h" // for TestPartResult, SuiteApiResolver
+#include "gtest/gtest_pred_impl.h" // for Test, EXPECT_EQ, AssertionResult
+#include <memory>                  // for unique_ptr, allocator, __shar...
+#include <string>                  // for string
+namespace caosdb::transaction {
+using caosdb::entity::Entity;
+using caosdb::entity::v1alpha1::FileDownloadResponse;
+using caosdb::entity::v1alpha1::FileUploadResponse;
+using caosdb::entity::v1alpha1::RegisterFileDownloadResponse;
+using caosdb::entity::v1alpha1::RegisterFileUploadResponse;
+using caosdb::entity::v1alpha1::RegistrationStatus;
+using caosdb::entity::v1alpha1::TransmissionStatus;
+
+
+// TODO(tf) this file is currently not used (see CMakeLists.txt)
+// Is it still necessary or is it obsolete due to test_transaction.cpp?
+// RegisterFileDownloadResponse is currently not defined by proto or the h
+// file.
+
+class test_file_transmission : public ::testing::Test {
+protected:
+  void SetUp() override {}
+
+  void TearDown() override {
+    // TODO(tf): delete all created entities
+  }
+};
+
+TEST_F(test_file_transmission, register_file_upload) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  auto transaction(connection->CreateTransaction());
+  RegisterFileUploadResponse response;
+  EXPECT_EQ(response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_UNSPECIFIED);
+
+  transaction->RegisterUploadFile(&response);
+
+  EXPECT_EQ(response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_ACCEPTED);
+  EXPECT_FALSE(response.registration_id().empty());
+}
+
+TEST_F(test_file_transmission, file_upload) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  auto transaction(connection->CreateTransaction());
+  RegisterFileUploadResponse registration_response;
+
+  transaction->RegisterUploadFile(&registration_response);
+  ASSERT_EQ(registration_response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_ACCEPTED);
+  auto registration_id = registration_response.registration_id();
+
+  FileUploadResponse upload_response;
+  transaction->UploadFile(&upload_response, registration_id);
+
+  EXPECT_EQ(upload_response.status(),
+            TransmissionStatus::TRANSMISSION_STATUS_GO_ON);
+}
+
+TEST_F(test_file_transmission, file_insertion) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  auto transaction(connection->CreateTransaction());
+  RegisterFileUploadResponse registration_response;
+
+  transaction->RegisterUploadFile(&registration_response);
+  ASSERT_EQ(registration_response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_ACCEPTED);
+  auto registration_id = registration_response.registration_id();
+
+  FileUploadResponse upload_response;
+  transaction->UploadFile(&upload_response, registration_id);
+
+  Entity file_entity;
+  file_entity.SetRole("File");
+  file_entity.SetFileTransmissionId(registration_id, "test.txt");
+  file_entity.SetFilePath("test.txt");
+
+  transaction->InsertEntity(&file_entity);
+  transaction->Execute();
+
+  auto cleanup_transaction(connection->CreateTransaction());
+  cleanup_transaction->DeleteById(transaction->GetResultSet().At(0).GetId());
+  cleanup_transaction->Execute();
+}
+
+TEST_F(test_file_transmission, file_download) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  auto upload_transaction(connection->CreateTransaction());
+  RegisterFileUploadResponse upload_registration_response;
+
+  upload_transaction->RegisterUploadFile(&upload_registration_response);
+  ASSERT_EQ(upload_registration_response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_ACCEPTED);
+  auto registration_id = upload_registration_response.registration_id();
+
+  FileUploadResponse upload_response;
+  upload_transaction->UploadFile(&upload_response, registration_id);
+
+  Entity file_entity;
+  file_entity.SetRole("File");
+  file_entity.SetFileTransmissionId(registration_id, "test.txt");
+  file_entity.SetFilePath("test.txt");
+
+  upload_transaction->InsertEntity(&file_entity);
+  upload_transaction->Execute();
+
+  // Download by entity_id
+  auto download_transaction(connection->CreateTransaction());
+  RegisterFileDownloadResponse download_registration_response;
+  RegisterFileDownloadRequest download_registration_request;
+  download_registration_request.add_files()->set_entity_id(
+      upload_transaction->GetResultSet().At(0).GetId());
+  download_transaction->RegisterDownloadFile(download_registration_request,
+                                             &download_registration_response);
+  ASSERT_EQ(download_registration_response.status(),
+            RegistrationStatus::REGISTRATION_STATUS_ACCEPTED);
+
+  FileDownloadResponse download_response;
+  download_transaction->DownloadFile(&download_response,
+                                     download_registration_response);
+
+  EXPECT_EQ(download_response.chunk().data(), "this is some data");
+
+  // CLEANUP
+  auto cleanup_transaction(connection->CreateTransaction());
+  cleanup_transaction->DeleteById(
+      upload_transaction->GetResultSet().At(0).GetId());
+  cleanup_transaction->Execute();
+}
+
+} // namespace caosdb::transaction
diff --git a/test/test_transaction.cpp b/test/test_transaction.cpp
index 79cdb12041a0f985745f495986506be452a27782..008093a2720ea7de89d2c03e06f65b92082cf5e1 100644
--- a/test/test_transaction.cpp
+++ b/test/test_transaction.cpp
@@ -18,18 +18,26 @@
  * along with this program. If not, see <https://www.gnu.org/licenses/>.
  *
  */
-#include "caosdb/connection.h"         // for Connection, ConnectionManager
-#include "caosdb/entity.h"             // for Entity, Messages, Message
+#include "caosdb/connection.h" // for Connection, ConnectionManager
+#include "caosdb/entity.h"     // for Entity, Messages, Message
+#include "caosdb/file_transmission/file_reader.h" // for FileReader
+#include "caosdb/file_transmission/file_writer.h" // for FileWriter
 #include "caosdb/message_code.h"       // for ENTITY_DOES_NOT_EXIST, Messag...
 #include "caosdb/status_code.h"        // for SUCCESS, StatusCode
-#include "caosdb/transaction.h"        // for Entity, Transaction, UniqueRe...
+#include "caosdb/transaction.h"        // for Entity, Transaction,...
 #include "caosdb/transaction_status.h" // for TransactionStatus, StatusCode
-#include "gtest/gtest-message.h"       // for Message
-#include "gtest/gtest-test-part.h"     // for TestPartResult, SuiteApiResolver
-#include "gtest/gtest_pred_impl.h"     // for Test, EXPECT_EQ, AssertionResult
-#include <memory>                      // for unique_ptr, allocator, __shar...
-#include <string>                      // for string
-#include <vector>                      // for vector
+#include <boost/filesystem/operations.hpp>  // for remove
+#include <boost/filesystem/path.hpp>        // for path
+#include <boost/filesystem/path_traits.hpp> // for filesystem
+#include <gtest/gtest-message.h>            // for Message
+#include <gtest/gtest-test-part.h> // for TestPartResult, SuiteApiResolver
+#include <gtest/gtest_pred_impl.h> // for Test, EXPECT_EQ, AssertionResult
+#include <iostream>
+#include <memory> // for unique_ptr, allocator, __shar...
+#include <string> // for string
+#include <vector> // for vector
+
+namespace fs = boost::filesystem;
 namespace caosdb::transaction {
 using caosdb::entity::Entity;
 using caosdb::entity::MessageCode;
@@ -38,15 +46,30 @@ using caosdb::entity::Property;
 
 class test_transaction : public ::testing::Test {
 protected:
-  void SetUp() override {}
+  fs::path test_upload_file_1;
+  fs::path test_download_file_1;
+
+  void SetUp() override {
+    test_upload_file_1 = fs::path("test_upload_file_1_delete_me.dat");
+    test_download_file_1 = fs::path("test_download_file_1_delete_me.dat");
+
+    FileWriter writer(test_upload_file_1);
+    std::string buffer(1024, 'c');
+    for (int i = 0; i < 8; i++) {
+      writer.write(buffer);
+    }
+  }
 
   void TearDown() override {
+    fs::remove(test_upload_file_1);
+    fs::remove(test_download_file_1);
+
     const auto &connection =
-      caosdb::connection::ConnectionManager::GetDefaultConnection();
+        caosdb::connection::ConnectionManager::GetDefaultConnection();
     auto query_transaction(connection->CreateTransaction());
     query_transaction->Query("FIND ENTITY WITH id > 99");
     query_transaction->Execute();
-    if (query_transaction->GetResultSet().Size() > 0) {
+    if (query_transaction->GetResultSet().size() > 0) {
       auto delete_transaction(connection->CreateTransaction());
       for (const Entity &entity : query_transaction->GetResultSet()) {
         delete_transaction->DeleteById(entity.GetId());
@@ -58,7 +81,7 @@ protected:
 
 TEST_F(test_transaction, DISABLED_retrieve_manufacturer_by_id) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   const auto *id = "107";
   const auto *role = "RecordType";
@@ -70,10 +93,9 @@ TEST_F(test_transaction, DISABLED_retrieve_manufacturer_by_id) {
   transaction->RetrieveById(id);
   transaction->Execute();
 
-  const auto &result_set =
-    dynamic_cast<const UniqueResult &>(transaction->GetResultSet());
+  const auto &result_set = transaction->GetResultSet();
 
-  const auto &entity = result_set.GetEntity();
+  const auto &entity = result_set.at(0);
   EXPECT_EQ(id, entity.GetId());
   EXPECT_EQ(name, entity.GetName());
   EXPECT_EQ(role, entity.GetRole());
@@ -83,7 +105,7 @@ TEST_F(test_transaction, DISABLED_retrieve_manufacturer_by_id) {
 
 TEST_F(test_transaction, retrieve_non_existing) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto transaction(connection->CreateTransaction());
 
@@ -95,20 +117,19 @@ TEST_F(test_transaction, retrieve_non_existing) {
   EXPECT_EQ(status.GetCode(), TransactionStatus::TRANSACTION_ERROR().GetCode());
   ASSERT_EQ(status.GetCode(), StatusCode::GENERIC_TRANSACTION_ERROR);
 
-  const auto &result_set =
-    dynamic_cast<const UniqueResult &>(transaction->GetResultSet());
+  const auto &result_set = transaction->GetResultSet();
 
-  const auto &entity = result_set.GetEntity();
+  const auto &entity = result_set.at(0);
   EXPECT_EQ(id, entity.GetId());
   EXPECT_TRUE(entity.HasErrors());
-  ASSERT_EQ(entity.GetErrors().Size(), 1);
-  EXPECT_EQ(entity.GetErrors().At(0).GetCode(),
+  ASSERT_EQ(entity.GetErrors().size(), 1);
+  EXPECT_EQ(entity.GetErrors().at(0).GetCode(),
             MessageCode::ENTITY_DOES_NOT_EXIST);
 }
 
 TEST_F(test_transaction, insert_without_delete) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto insert_transaction(connection->CreateTransaction());
 
@@ -123,22 +144,21 @@ TEST_F(test_transaction, insert_without_delete) {
   ASSERT_TRUE(insert_status.IsTerminated());
   ASSERT_FALSE(insert_status.IsError());
 
-  const auto &insert_result_set =
-    dynamic_cast<const UniqueResult &>(insert_transaction->GetResultSet());
+  const auto &insert_result_set = insert_transaction->GetResultSet();
 
-  const auto &new_entity = insert_result_set.GetEntity();
+  const auto &new_entity = insert_result_set.at(0);
   EXPECT_FALSE(new_entity.GetId().empty());
   EXPECT_FALSE(new_entity.HasErrors());
   // Should have a warning since it has no properties
   EXPECT_TRUE(new_entity.HasWarnings());
-  EXPECT_EQ(new_entity.GetWarnings().Size(), 1);
-  EXPECT_EQ(new_entity.GetWarnings().At(0).GetCode(),
+  EXPECT_EQ(new_entity.GetWarnings().size(), 1);
+  EXPECT_EQ(new_entity.GetWarnings().at(0).GetCode(),
             MessageCode::ENTITY_HAS_NO_PROPERTIES);
 }
 
 TEST_F(test_transaction, insert_delete) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto insert_transaction(connection->CreateTransaction());
 
@@ -153,16 +173,15 @@ TEST_F(test_transaction, insert_delete) {
   ASSERT_TRUE(insert_status.IsTerminated());
   ASSERT_FALSE(insert_status.IsError());
 
-  const auto &insert_result_set =
-    dynamic_cast<const UniqueResult &>(insert_transaction->GetResultSet());
+  const auto &insert_result_set = insert_transaction->GetResultSet();
 
-  const auto &new_entity = insert_result_set.GetEntity();
+  const auto &new_entity = insert_result_set.at(0);
   EXPECT_FALSE(new_entity.GetId().empty());
   EXPECT_FALSE(new_entity.HasErrors());
   // Should have a warning since it has no properties
   EXPECT_TRUE(new_entity.HasWarnings());
-  EXPECT_EQ(new_entity.GetWarnings().Size(), 1);
-  EXPECT_EQ(new_entity.GetWarnings().At(0).GetCode(),
+  EXPECT_EQ(new_entity.GetWarnings().size(), 1);
+  EXPECT_EQ(new_entity.GetWarnings().at(0).GetCode(),
             MessageCode::ENTITY_HAS_NO_PROPERTIES);
 
   auto delete_transaction(connection->CreateTransaction());
@@ -175,17 +194,16 @@ TEST_F(test_transaction, insert_delete) {
   ASSERT_TRUE(delete_status.IsTerminated());
   ASSERT_FALSE(delete_status.IsError());
 
-  const auto &delete_result_set =
-    dynamic_cast<const UniqueResult &>(delete_transaction->GetResultSet());
+  const auto &delete_result_set = delete_transaction->GetResultSet();
 
-  const auto &deleted_entity = delete_result_set.GetEntity();
+  const auto &deleted_entity = delete_result_set.at(0);
   EXPECT_EQ(deleted_entity.GetId(), new_entity.GetId());
   EXPECT_FALSE(deleted_entity.HasErrors());
 }
 
 TEST_F(test_transaction, insert_delete_with_parent) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto insert_transaction(connection->CreateTransaction());
 
@@ -200,10 +218,9 @@ TEST_F(test_transaction, insert_delete_with_parent) {
   ASSERT_TRUE(insert_status.IsTerminated());
   ASSERT_FALSE(insert_status.IsError());
 
-  const auto &insert_result_set =
-    dynamic_cast<const UniqueResult &>(insert_transaction->GetResultSet());
+  const auto &insert_result_set = insert_transaction->GetResultSet();
 
-  const auto &inserted_rt = insert_result_set.GetEntity();
+  const auto &inserted_rt = insert_result_set.at(0);
 
   Entity rec;
   rec.SetRole("Record");
@@ -223,10 +240,9 @@ TEST_F(test_transaction, insert_delete_with_parent) {
   ASSERT_TRUE(rec_insert_status.IsTerminated());
   ASSERT_FALSE(rec_insert_status.IsError());
 
-  const auto &rec_result_set =
-    dynamic_cast<const UniqueResult &>(rec_transaction->GetResultSet());
+  const auto &rec_result_set = rec_transaction->GetResultSet();
 
-  const auto &inserted_rec = rec_result_set.GetEntity();
+  const auto &inserted_rec = rec_result_set.at(0);
 
   EXPECT_FALSE(inserted_rec.GetId().empty());
 
@@ -240,14 +256,13 @@ TEST_F(test_transaction, insert_delete_with_parent) {
   ASSERT_TRUE(rec_retrieve_status.IsTerminated());
   ASSERT_FALSE(rec_retrieve_status.IsError());
 
-  const auto &retrieve_result_set =
-    dynamic_cast<const UniqueResult &>(retrieve_transaction->GetResultSet());
-  const auto &retrieved_rec = retrieve_result_set.GetEntity();
+  const auto &retrieve_result_set = retrieve_transaction->GetResultSet();
+  const auto &retrieved_rec = retrieve_result_set.at(0);
 
   EXPECT_EQ(retrieved_rec.GetName(), rec.GetName());
-  EXPECT_EQ(retrieved_rec.GetParents().Size(), 1);
-  EXPECT_EQ(retrieved_rec.GetParents().At(0).GetId(), inserted_rt.GetId());
-  EXPECT_EQ(retrieved_rec.GetParents().At(0).GetName(), rt.GetName());
+  EXPECT_EQ(retrieved_rec.GetParents().size(), 1);
+  EXPECT_EQ(retrieved_rec.GetParents().at(0).GetId(), inserted_rt.GetId());
+  EXPECT_EQ(retrieved_rec.GetParents().at(0).GetName(), rt.GetName());
 
   auto rec_deletion(connection->CreateTransaction());
 
@@ -272,7 +287,7 @@ TEST_F(test_transaction, insert_delete_with_parent) {
 
 TEST_F(test_transaction, insert_delete_with_property) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   // Create and insert property
   Entity prop_ent;
@@ -289,10 +304,9 @@ TEST_F(test_transaction, insert_delete_with_property) {
   ASSERT_TRUE(prop_insert_status.IsTerminated());
   ASSERT_FALSE(prop_insert_status.IsError());
 
-  const auto &prop_result_set =
-    dynamic_cast<const UniqueResult &>(prop_insertion->GetResultSet());
+  const auto &prop_result_set = prop_insertion->GetResultSet();
 
-  const auto &inserted_prop = prop_result_set.GetEntity();
+  const auto &inserted_prop = prop_result_set.at(0);
   EXPECT_FALSE(inserted_prop.GetId().empty());
 
   // create and insert record type with the above property
@@ -304,6 +318,7 @@ TEST_F(test_transaction, insert_delete_with_property) {
   Entity rt;
   rt.SetRole("RecordType");
   rt.SetName("TestRT");
+  rt.SetDescription("Some description");
   rt.AppendProperty(prop_rt);
 
   auto rt_insertion(connection->CreateTransaction());
@@ -315,10 +330,9 @@ TEST_F(test_transaction, insert_delete_with_property) {
   ASSERT_TRUE(rt_insert_status.IsTerminated());
   ASSERT_FALSE(rt_insert_status.IsError());
 
-  const auto &rt_result_set =
-    dynamic_cast<const UniqueResult &>(rt_insertion->GetResultSet());
+  const auto &rt_result_set = rt_insertion->GetResultSet();
 
-  const auto &inserted_rt = rt_result_set.GetEntity();
+  const auto &inserted_rt = rt_result_set.at(0);
   EXPECT_FALSE(inserted_rt.GetId().empty());
 
   // retrieve inserted rt for testing
@@ -330,15 +344,15 @@ TEST_F(test_transaction, insert_delete_with_property) {
   ASSERT_TRUE(rt_retrieve_status.IsTerminated());
   ASSERT_FALSE(rt_retrieve_status.IsError());
 
-  const auto &rt_retrieve_results =
-    dynamic_cast<const UniqueResult &>(rt_retrieval->GetResultSet());
+  const auto &rt_retrieve_results = rt_retrieval->GetResultSet();
 
-  const auto &retrieved_rt = rt_retrieve_results.GetEntity();
+  const auto &retrieved_rt = rt_retrieve_results.at(0);
   EXPECT_EQ(inserted_rt.GetId(), retrieved_rt.GetId());
   EXPECT_EQ(rt.GetName(), retrieved_rt.GetName());
-  EXPECT_EQ(retrieved_rt.GetProperties().Size(), 1);
+  EXPECT_EQ(rt.GetDescription(), retrieved_rt.GetDescription());
+  EXPECT_EQ(retrieved_rt.GetProperties().size(), 1);
 
-  const auto &retrieved_prop_rt = retrieved_rt.GetProperties().At(0);
+  const auto &retrieved_prop_rt = retrieved_rt.GetProperties().at(0);
   EXPECT_EQ(retrieved_prop_rt.GetName(), prop_ent.GetName());
   EXPECT_EQ(retrieved_prop_rt.GetId(), inserted_prop.GetId());
   EXPECT_EQ(retrieved_prop_rt.GetDatatype(), prop_ent.GetDatatype());
@@ -370,10 +384,9 @@ TEST_F(test_transaction, insert_delete_with_property) {
   ASSERT_TRUE(rec_insert_status.IsTerminated());
   ASSERT_FALSE(rec_insert_status.IsError());
 
-  const auto &rec_result_set =
-    dynamic_cast<const UniqueResult &>(rec_insertion->GetResultSet());
+  const auto &rec_result_set = rec_insertion->GetResultSet();
 
-  const auto &inserted_rec = rec_result_set.GetEntity();
+  const auto &inserted_rec = rec_result_set.at(0);
   EXPECT_FALSE(inserted_rec.GetId().empty());
 
   // Retrieve the record and verify paretn and property
@@ -385,20 +398,20 @@ TEST_F(test_transaction, insert_delete_with_property) {
   ASSERT_TRUE(rec_retrieve_status.IsTerminated());
   ASSERT_FALSE(rec_retrieve_status.IsError());
 
-  const auto &rec_retrieve_results =
-    dynamic_cast<const UniqueResult &>(rec_retrieval->GetResultSet());
+  const auto &rec_retrieve_results = rec_retrieval->GetResultSet();
 
-  const auto &retrieved_rec = rec_retrieve_results.GetEntity();
+  const auto &retrieved_rec = rec_retrieve_results.at(0);
   EXPECT_EQ(rec.GetName(), retrieved_rec.GetName());
   EXPECT_EQ(inserted_rec.GetId(), retrieved_rec.GetId());
-  EXPECT_EQ(retrieved_rec.GetParents().Size(), 1);
-  EXPECT_EQ(retrieved_rec.GetProperties().Size(), 1);
+  EXPECT_EQ(retrieved_rec.GetParents().size(), 1);
+  EXPECT_EQ(retrieved_rec.GetProperties().size(), 1);
 
-  const auto &retrieved_parent_rec = retrieved_rec.GetParents().At(0);
+  const auto &retrieved_parent_rec = retrieved_rec.GetParents().at(0);
   EXPECT_EQ(retrieved_parent_rec.GetName(), rt.GetName());
   EXPECT_EQ(retrieved_parent_rec.GetId(), inserted_rt.GetId());
+  EXPECT_EQ(retrieved_parent_rec.GetDescription(), rt.GetDescription());
 
-  const auto &retrieved_prop_rec = retrieved_rec.GetProperties().At(0);
+  const auto &retrieved_prop_rec = retrieved_rec.GetProperties().at(0);
   EXPECT_EQ(retrieved_prop_rec.GetName(), prop_ent.GetName());
   EXPECT_EQ(retrieved_prop_rec.GetId(), inserted_prop.GetId());
   EXPECT_EQ(retrieved_prop_rec.GetDatatype(), prop_ent.GetDatatype());
@@ -407,7 +420,7 @@ TEST_F(test_transaction, insert_delete_with_property) {
 
 TEST_F(test_transaction, test_multi_retrieve) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto transaction(connection->CreateTransaction());
 
@@ -418,24 +431,27 @@ TEST_F(test_transaction, test_multi_retrieve) {
   auto status = transaction->WaitForIt();
 
   ASSERT_TRUE(status.IsTerminated());
-  ASSERT_FALSE(status.IsError());
+  // Should have an error since entity 22 doesn't exist
+  ASSERT_TRUE(status.IsError());
 
   const auto &result_set = transaction->GetResultSet();
 
-  EXPECT_EQ(result_set.Size(), 3);
-  EXPECT_EQ(result_set.At(1).GetId(), "21");
-  EXPECT_EQ(result_set.At(1).GetName(), "unit");
-  EXPECT_FALSE(result_set.At(1).HasErrors());
+  EXPECT_EQ(result_set.size(), 3);
+  EXPECT_EQ(result_set.at(1).GetId(), "21");
+  EXPECT_EQ(result_set.at(1).GetName(), "unit");
+  // Exists so should be fine ...
+  EXPECT_FALSE(result_set.at(1).HasErrors());
 
-  EXPECT_EQ(result_set.At(2).GetId(), "22");
-  EXPECT_TRUE(result_set.At(2).HasErrors());
-  EXPECT_EQ(result_set.At(2).GetErrors().At(0).GetCode(),
+  // ... but this does not
+  EXPECT_EQ(result_set.at(2).GetId(), "22");
+  EXPECT_TRUE(result_set.at(2).HasErrors());
+  EXPECT_EQ(result_set.at(2).GetErrors().at(0).GetCode(),
             MessageCode::ENTITY_DOES_NOT_EXIST);
 }
 
 TEST_F(test_transaction, insert_update_delete) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   // INSERT
   auto insert_transaction(connection->CreateTransaction());
@@ -451,10 +467,9 @@ TEST_F(test_transaction, insert_update_delete) {
   ASSERT_TRUE(insert_status.IsTerminated());
   ASSERT_FALSE(insert_status.IsError());
 
-  const auto &insert_result_set =
-    dynamic_cast<const UniqueResult &>(insert_transaction->GetResultSet());
+  const auto &insert_result_set = insert_transaction->GetResultSet();
 
-  const auto &new_entity = insert_result_set.GetEntity();
+  const auto &new_entity = insert_result_set.at(0);
   EXPECT_FALSE(new_entity.GetId().empty());
   EXPECT_FALSE(new_entity.HasErrors());
 
@@ -465,7 +480,7 @@ TEST_F(test_transaction, insert_update_delete) {
 
   // UPDATE
   auto update_transaction(connection->CreateTransaction());
-  auto update_entity(retrieve_transaction->GetResultSet().At(0));
+  auto update_entity(retrieve_transaction->GetResultSet().at(0));
   update_entity.SetName("RT1-Update");
 
   update_transaction->UpdateEntity(&update_entity);
@@ -475,8 +490,8 @@ TEST_F(test_transaction, insert_update_delete) {
   ASSERT_TRUE(update_status.IsTerminated());
   ASSERT_FALSE(update_status.IsError());
 
-  EXPECT_EQ(update_transaction->GetResultSet().Size(), 1);
-  const auto &updated_entity = update_transaction->GetResultSet().At(0);
+  EXPECT_EQ(update_transaction->GetResultSet().size(), 1);
+  const auto &updated_entity = update_transaction->GetResultSet().at(0);
 
   EXPECT_EQ(updated_entity.GetId(), new_entity.GetId());
   EXPECT_FALSE(updated_entity.HasErrors());
@@ -492,17 +507,16 @@ TEST_F(test_transaction, insert_update_delete) {
   ASSERT_TRUE(delete_status.IsTerminated());
   ASSERT_FALSE(delete_status.IsError());
 
-  const auto &delete_result_set =
-    dynamic_cast<const UniqueResult &>(delete_transaction->GetResultSet());
+  const auto &delete_result_set = delete_transaction->GetResultSet();
 
-  const auto &deleted_entity = delete_result_set.GetEntity();
+  const auto &deleted_entity = delete_result_set.at(0);
   EXPECT_EQ(deleted_entity.GetId(), new_entity.GetId());
   EXPECT_FALSE(deleted_entity.HasErrors());
 }
 
 TEST_F(test_transaction, test_query) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   auto insert_transaction(connection->CreateTransaction());
 
@@ -517,33 +531,34 @@ TEST_F(test_transaction, test_query) {
   ASSERT_TRUE(insert_status.IsTerminated());
   ASSERT_FALSE(insert_status.IsError());
 
-  const auto &insert_result_set =
-    dynamic_cast<const UniqueResult &>(insert_transaction->GetResultSet());
+  const auto &insert_result_set = insert_transaction->GetResultSet();
 
-  const auto &new_entity = insert_result_set.GetEntity();
+  const auto &new_entity = insert_result_set.at(0);
   EXPECT_FALSE(new_entity.GetId().empty());
   EXPECT_FALSE(new_entity.HasErrors());
 
   auto query_transaction(connection->CreateTransaction());
   query_transaction->Query("FIND ENTITY WITH id = " + new_entity.GetId());
   query_transaction->Execute();
-  EXPECT_EQ(query_transaction->GetResultSet().Size(), 1);
-  EXPECT_EQ(query_transaction->GetResultSet().At(0).GetId(),
+  EXPECT_EQ(query_transaction->GetResultSet().size(), 1);
+  EXPECT_EQ(query_transaction->GetResultSet().at(0).GetId(),
             new_entity.GetId());
   // No count query, so no count result should be present
   EXPECT_TRUE((query_transaction->GetCountResult() < 0));
 
   auto count_query_trans(connection->CreateTransaction());
+  std::cout << "Creating count query ..." << std::endl;
   count_query_trans->Query("COUNT ENTITY WITH id = " + new_entity.GetId());
+  std::cout << "Executing count query ..." << std::endl;
   count_query_trans->Execute();
   // No result set in a count query
-  EXPECT_EQ(count_query_trans->GetResultSet().Size(), 0);
+  EXPECT_EQ(count_query_trans->GetResultSet().size(), 0);
   EXPECT_EQ(count_query_trans->GetCountResult(), 1);
 }
 
 TEST_F(test_transaction, test_query_with_retrieve) {
   const auto &connection =
-    caosdb::connection::ConnectionManager::GetDefaultConnection();
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
 
   // rt1
   Entity rt1;
@@ -559,10 +574,9 @@ TEST_F(test_transaction, test_query_with_retrieve) {
   ASSERT_TRUE(insert_rt1_status.IsTerminated());
   ASSERT_FALSE(insert_rt1_status.IsError());
 
-  const auto &insert_rt1_results =
-    dynamic_cast<const UniqueResult &>(insert_rt1_transaction->GetResultSet());
+  const auto &insert_rt1_results = insert_rt1_transaction->GetResultSet();
 
-  const auto &inserted_rt1 = insert_rt1_results.GetEntity();
+  const auto &inserted_rt1 = insert_rt1_results.at(0);
   EXPECT_FALSE(inserted_rt1.GetId().empty());
   EXPECT_FALSE(inserted_rt1.HasErrors());
 
@@ -580,10 +594,9 @@ TEST_F(test_transaction, test_query_with_retrieve) {
   ASSERT_TRUE(insert_rt2_status.IsTerminated());
   ASSERT_FALSE(insert_rt2_status.IsError());
 
-  const auto &insert_rt2_results =
-    dynamic_cast<const UniqueResult &>(insert_rt2_transaction->GetResultSet());
+  const auto &insert_rt2_results = insert_rt2_transaction->GetResultSet();
 
-  const auto &inserted_rt2 = insert_rt2_results.GetEntity();
+  const auto &inserted_rt2 = insert_rt2_results.at(0);
   EXPECT_FALSE(inserted_rt2.GetId().empty());
   EXPECT_FALSE(inserted_rt2.HasErrors());
 
@@ -601,10 +614,9 @@ TEST_F(test_transaction, test_query_with_retrieve) {
   ASSERT_TRUE(insert_rt3_status.IsTerminated());
   ASSERT_FALSE(insert_rt3_status.IsError());
 
-  const auto &insert_rt3_results =
-    dynamic_cast<const UniqueResult &>(insert_rt3_transaction->GetResultSet());
+  const auto &insert_rt3_results = insert_rt3_transaction->GetResultSet();
 
-  const auto &inserted_rt3 = insert_rt3_results.GetEntity();
+  const auto &inserted_rt3 = insert_rt3_results.at(0);
   EXPECT_FALSE(inserted_rt3.GetId().empty());
   EXPECT_FALSE(inserted_rt3.HasErrors());
 
@@ -619,7 +631,7 @@ TEST_F(test_transaction, test_query_with_retrieve) {
   ASSERT_FALSE(find_status.IsError());
 
   const auto &find_results = find_transaction->GetResultSet();
-  EXPECT_EQ(find_results.Size(), 3);
+  EXPECT_EQ(find_results.size(), 3);
 
   // only retrieve rt1 and rt2 by id
   const std::vector<std::string> ids = {inserted_rt1.GetId(),
@@ -637,7 +649,7 @@ TEST_F(test_transaction, test_query_with_retrieve) {
   ASSERT_FALSE(find_and_retrieve_status.IsError());
 
   const auto &result_set_a = find_and_retrieve->GetResultSet();
-  EXPECT_EQ(result_set_a.Size(), 3);
+  EXPECT_EQ(result_set_a.size(), 3);
 
   // retrieve rt1 and rt2 by ID and count all TestRTs
   auto count_and_retrieve(connection->CreateTransaction());
@@ -652,8 +664,85 @@ TEST_F(test_transaction, test_query_with_retrieve) {
 
   const auto &result_set_b = count_and_retrieve->GetResultSet();
   // TODO(fspreck) Re-enable once we implemented this
-  // EXPECT_EQ(result_set_b.Size(), 2);
+  // EXPECT_EQ(result_set_b.size(), 2);
   EXPECT_EQ(count_and_retrieve->GetCountResult(), 3);
 }
 
+TEST_F(test_transaction, test_file_upload) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  Entity file;
+  file.SetRole("File");
+  file.SetFilePath("test.txt");
+  file.SetLocalPath(test_upload_file_1);
+
+  auto insert_transaction(connection->CreateTransaction());
+  insert_transaction->InsertEntity(&file);
+  insert_transaction->ExecuteAsynchronously();
+
+  auto insert_status = insert_transaction->WaitForIt();
+
+  ASSERT_TRUE(insert_status.IsTerminated());
+  EXPECT_EQ(insert_status.GetCode(), StatusCode::SUCCESS);
+
+  const auto &insert_results = insert_transaction->GetResultSet();
+
+  const auto &inserted_file = insert_results.at(0);
+  EXPECT_FALSE(inserted_file.GetId().empty());
+  EXPECT_FALSE(inserted_file.HasErrors());
+
+  // Check file once more
+  auto count_query(connection->CreateTransaction());
+  count_query->Query("COUNT FILE WHICH IS STORED AT 'test.txt'");
+  count_query->ExecuteAsynchronously();
+  auto count_and_retrieve_status = count_query->WaitForIt();
+  ASSERT_TRUE(count_and_retrieve_status.IsTerminated());
+  ASSERT_FALSE(count_and_retrieve_status.IsError());
+  EXPECT_EQ(count_query->GetCountResult(), 1);
+}
+
+TEST_F(test_transaction, test_file_up_n_download) {
+  const auto &connection =
+      caosdb::connection::ConnectionManager::GetDefaultConnection();
+
+  Entity file;
+  file.SetRole("File");
+  file.SetFilePath("test.txt");
+  file.SetLocalPath(test_upload_file_1);
+
+  auto insert_transaction(connection->CreateTransaction());
+  insert_transaction->InsertEntity(&file);
+  insert_transaction->Execute();
+
+  const auto &insert_results = insert_transaction->GetResultSet();
+
+  const auto &inserted_file = insert_results.at(0);
+  ASSERT_FALSE(inserted_file.GetId().empty());
+  ASSERT_FALSE(inserted_file.HasErrors());
+
+  auto download_transaction(connection->CreateTransaction());
+  download_transaction->RetrieveAndDownloadFilesById(
+      inserted_file.GetId(), test_download_file_1.string());
+  download_transaction->ExecuteAsynchronously();
+  ASSERT_EQ(download_transaction->WaitForIt().GetCode(), StatusCode::SUCCESS);
+
+  const auto &download_results = download_transaction->GetResultSet();
+  ASSERT_EQ(download_results.size(), 1);
+
+  const auto &downloaded_file = download_results.at(0);
+  ASSERT_FALSE(downloaded_file.GetId().empty());
+  ASSERT_FALSE(downloaded_file.HasErrors());
+  EXPECT_EQ(downloaded_file.GetLocalPath().string(),
+            test_download_file_1.string());
+
+  FileReader reader_remote(test_upload_file_1);
+  std::string buffer_local(1024, 'c');
+  std::string buffer_remote(1024, 'c');
+  for (int i = 0; i < 8; i++) {
+    reader_remote.read(buffer_remote);
+    EXPECT_EQ(buffer_remote, buffer_local);
+  }
+}
+
 } // namespace caosdb::transaction