Added a fake file writer (writes to string instead of file) (#1101)

Added fake filer writer which writes the output to a string instead of a file.

This will help writing tests for classes that use the file writer interface to write data.

cartographer/BUILD.bazel

@@ -48,6 +48,29 @@ cc_fix_config(
     visibility = ["//visibility:private"],
 )
 
+TEST_LIBRARY_SRCS = glob([
+    "**/*test_helpers.cc",
+    "**/fake_*.cc",
+    "**/mock_*.cc",
+])
+
+TEST_LIBRARY_HDRS = glob([
+    "**/*test_helpers.h",
+    "**/fake_*.h",
+    "**/mock_*.h",
+])
+
+cc_library(
+    name = "cartographer_test_library",
+    testonly = 1,
+    srcs = TEST_LIBRARY_SRCS,
+    hdrs = TEST_LIBRARY_HDRS,
+    deps = [
+        ":cartographer",
+        "@com_google_googletest//:gtest",
+    ],
+)
+
 cc_library(
     name = "cartographer",
     srcs = glob(
@@ -57,13 +80,16 @@ cc_library(
         exclude = [
             "**/*_main.cc",
             "**/*_test.cc",
-        ],
+        ] + TEST_LIBRARY_SRCS,
     ),
     hdrs = [
         "common/config.h",
-    ] + glob([
-        "**/*.h",
-    ]),
+    ] + glob(
+        [
+            "**/*.h",
+        ],
+        exclude = TEST_LIBRARY_HDRS,
+    ),
     copts = ["-Wno-sign-compare"],
     includes = ["."],
     deps = [
@@ -83,6 +109,7 @@ cc_library(
     data = ["//:configuration_files"],
     deps = [
         ":cartographer",
+        ":cartographer_test_library",
         "@com_google_googletest//:gtest_main",
     ],
 ) for src in glob(

cartographer/cloud/BUILD.bazel

@@ -94,6 +94,7 @@ cc_binary(
     tags = ["exclusive"],
     deps = [
         ":cartographer_grpc",
+        "//cartographer:cartographer_test_library",
         "@com_google_googletest//:gtest_main",
     ],
 ) for src in glob(

cartographer/io/fake_file_writer.cc

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2018 The Cartographer Authors
+ *
+ * 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.
+ */
+
+#include "cartographer/io/fake_file_writer.h"
+
+#include "glog/logging.h"
+#include "gtest/gtest.h"
+
+namespace cartographer {
+namespace io {
+
+FakeFileWriter::FakeFileWriter(const std::string& filename,
+                               std::shared_ptr<std::vector<char>> content)
+    : is_closed_(false), content_(content), filename_(filename) {
+  CHECK(content != nullptr);
+}
+
+bool FakeFileWriter::Write(const char* const data, const size_t len) {
+  EXPECT_FALSE(is_closed_);
+  content_->insert(content_->end(), data, data + len);
+  return true;
+}
+
+bool FakeFileWriter::Close() {
+  EXPECT_FALSE(is_closed_);
+  is_closed_ = true;
+  return true;
+}
+
+bool FakeFileWriter::WriteHeader(const char* const data, const size_t len) {
+  EXPECT_FALSE(is_closed_);
+  if (content_->size() < len) {
+    content_->resize(len);
+  }
+  std::copy(data, data + len, content_->begin());
+  return true;
+}
+
+std::string FakeFileWriter::GetFilename() { return filename_; }
+
+}  // namespace io
+}  // namespace cartographer

cartographer/io/fake_file_writer.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 The Cartographer Authors
+ *
+ * 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.
+ */
+
+#ifndef CARTOGRAPHER_IO_FAKE_FILE_WRITER_H_
+#define CARTOGRAPHER_IO_FAKE_FILE_WRITER_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "cartographer/io/file_writer.h"
+
+namespace cartographer {
+namespace io {
+
+// Fakes a FileWriter by just writing the data to a std::vector<char>.
+class FakeFileWriter : public FileWriter {
+ public:
+  FakeFileWriter(const std::string& filename,
+                 std::shared_ptr<std::vector<char>> content);
+  ~FakeFileWriter() override = default;
+
+  bool WriteHeader(const char* data, size_t len) override;
+  bool Write(const char* data, size_t len) override;
+  bool Close() override;
+  std::string GetFilename() override;
+
+ private:
+  bool is_closed_;
+  std::shared_ptr<std::vector<char>> content_;
+  std::string filename_;
+};
+
+}  // namespace io
+}  // namespace cartographer
+
+#endif  // CARTOGRAPHER_IO_FAKE_FILE_WRITER_H_

cartographer/io/fake_file_writer_test.cc

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2018 The Cartographer Authors
+ *
+ * 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.
+ */
+
+#include <vector>
+
+#include "cartographer/io/fake_file_writer.h"
+#include "glog/logging.h"
+#include "gtest/gtest.h"
+
+namespace cartographer {
+namespace io {
+namespace {
+
+std::string toString(const std::vector<char>& data) {
+  return std::string(data.data(), data.size());
+}
+
+TEST(FakeFileWriter, Filename) {
+  auto content = std::make_shared<std::vector<char>>();
+  FakeFileWriter writer("file", content);
+  EXPECT_EQ("file", writer.GetFilename());
+}
+
+TEST(FakeFileWriter, CloseStream) {
+  auto content = std::make_shared<std::vector<char>>();
+  FakeFileWriter writer("file", content);
+  EXPECT_TRUE(writer.Close());
+  EXPECT_EQ("", toString(*content));
+}
+
+TEST(FakeFileWriter, WriteHeader) {
+  auto content = std::make_shared<std::vector<char>>();
+  const std::string header("dummy header");
+  const std::string header_2("dummy header 2");
+  FakeFileWriter writer("file", content);
+
+  EXPECT_TRUE(writer.WriteHeader(header.c_str(), header.size()));
+  EXPECT_EQ("dummy header", toString(*content));
+
+  EXPECT_TRUE(writer.WriteHeader(header_2.c_str(), header_2.size()));
+  EXPECT_EQ("dummy header 2", toString(*content));
+
+  EXPECT_TRUE(writer.Close());
+  EXPECT_EQ("dummy header 2", toString(*content));
+}
+
+TEST(FakeFileWriter, Write) {
+  auto content = std::make_shared<std::vector<char>>();
+  const std::vector<std::string> data_stream = {"data 1", "data 2"};
+  FakeFileWriter writer("file", content);
+
+  for (const auto& data : data_stream) {
+    EXPECT_TRUE(writer.Write(data.c_str(), data.size()));
+  }
+
+  EXPECT_EQ("data 1data 2", toString(*content));
+  EXPECT_TRUE(writer.Close());
+  EXPECT_EQ("data 1data 2", toString(*content));
+}
+
+TEST(FakeFileWriter, HeaderAndWrite) {
+  auto content = std::make_shared<std::vector<char>>();
+  const std::string header("dummy header");
+  const std::vector<std::string> data_stream = {"data 1", "data 2"};
+  FakeFileWriter writer("file", content);
+
+  EXPECT_TRUE(writer.WriteHeader(header.c_str(), header.size()));
+  EXPECT_EQ("dummy header", toString(*content));
+
+  for (const auto& data : data_stream) {
+    EXPECT_TRUE(writer.Write(data.c_str(), data.size()));
+  }
+
+  EXPECT_TRUE(writer.Close());
+  EXPECT_EQ("dummy headerdata 1data 2", toString(*content));
+}
+
+TEST(FakeFileWriter, WriteTerminatedString) {
+  auto content = std::make_shared<std::vector<char>>();
+  std::vector<char> data_stream = {'d', 'a', 't', 'a', '\0', ' ', '1'};
+  FakeFileWriter writer("file", content);
+  EXPECT_TRUE(writer.Write(data_stream.data(), data_stream.size()));
+  EXPECT_EQ(data_stream, *content);
+}
+
+TEST(FakeFileWriter, WriteTerminatedHeaderString) {
+  auto content = std::make_shared<std::vector<char>>();
+  std::vector<char> header = {'h', 'e', 'a', 'd', '\0', ' ', 'e', 'r'};
+  FakeFileWriter writer("file", content);
+  EXPECT_TRUE(writer.WriteHeader(header.data(), header.size()));
+  EXPECT_EQ(header, *content);
+}
+
+TEST(FakeFileWriter, HeaderAndWriteTerminatedString) {
+  auto content = std::make_shared<std::vector<char>>();
+  std::vector<char> header = {'d', 'a', 't', 'a', '\0', ' ', '1'};
+  std::vector<char> data = {'h', 'e', 'a', 'd', '\0', ' ', 'e', 'r'};
+
+  FakeFileWriter writer("file", content);
+  EXPECT_TRUE(writer.WriteHeader(header.data(), header.size()));
+  EXPECT_EQ(header, *content);
+
+  EXPECT_TRUE(writer.Write(data.data(), data.size()));
+
+  std::vector<char> expected_output = header;
+  expected_output.insert(expected_output.end(), data.begin(), data.end());
+
+  EXPECT_EQ(expected_output, *content);
+
+  EXPECT_TRUE(writer.Close());
+  EXPECT_EQ(expected_output, *content);
+}
+
+}  // namespace
+}  // namespace io
+}  // namespace cartographer