Combine file stream reader unittests

These are all separate but different unittests that have grown
organically apart from each other, combine into a single typed test
so that future file stream reader unittests can reuse this structure.

The one unfortunate part about doing it this way is that it requires a
lot more `this->` everywhere because of C++ templates.  However,
the alternative of having a test fixture with a bunch of switch
statements for the different types seems strictly worse.

Change-Id: Id56bc28391e1a640748691cb383a19291c47fc51
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2406718
Commit-Queue: Nick Harper <nharper@chromium.org>
Auto-Submit: enne <enne@chromium.org>
Reviewed-by: Nick Harper <nharper@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807092}

net/base/file_stream_context.cc

@@ -113,6 +113,11 @@ void FileStream::Context::Seek(int64_t offset,
                                Int64CompletionOnceCallback callback) {
   DCHECK(!async_in_progress_);
 
+  if (offset < 0) {
+    std::move(callback).Run(net::ERR_INVALID_ARGUMENT);
+    return;
+  }
+
   bool posted = base::PostTaskAndReplyWithResult(
       task_runner_.get(), FROM_HERE,
       base::BindOnce(&Context::SeekFileImpl, base::Unretained(this), offset),

storage/browser/BUILD.gn

@@ -275,6 +275,8 @@ source_set("unittests") {
     "file_system/copy_or_move_operation_delegate_unittest.cc",
     "file_system/dragged_file_util_unittest.cc",
     "file_system/external_mount_points_unittest.cc",
+    "file_system/file_stream_reader_test.cc",
+    "file_system/file_stream_reader_test.h",
     "file_system/file_stream_test_utils.cc",
     "file_system/file_stream_test_utils.h",
     "file_system/file_system_context_unittest.cc",

storage/browser/file_system/file_stream_reader_test.cc

@@ -0,0 +1,12 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "storage/browser/file_system/file_stream_reader_test.h"
+
+namespace storage {
+
+const base::StringPiece FileStreamReaderTest::kTestFileName;
+const base::StringPiece FileStreamReaderTest::kTestData;
+
+}  // namespace storage

storage/browser/file_system/file_stream_reader_test.h

@@ -0,0 +1,276 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef STORAGE_BROWSER_FILE_SYSTEM_FILE_STREAM_READER_TEST_H_
+#define STORAGE_BROWSER_FILE_SYSTEM_FILE_STREAM_READER_TEST_H_
+
+#include "base/bind_helpers.h"
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/single_thread_task_runner.h"
+#include "base/test/task_environment.h"
+#include "base/threading/thread.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/base/test_completion_callback.h"
+#include "storage/browser/file_system/file_stream_reader.h"
+#include "storage/browser/file_system/file_stream_test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace storage {
+
+// An interface for derived FileStreamReader to implement.
+// This allows multiple FileStreamReader implementations can share the
+// same test framework.  Tests should implement CreateFileReader, WriteFile, and
+// TouchFile to manipulate files for their particular implementation.
+class FileStreamReaderTest : public testing::Test {
+ public:
+  static constexpr base::StringPiece kTestFileName = "test.dat";
+  static constexpr base::StringPiece kTestData = "0123456789";
+
+  virtual std::unique_ptr<FileStreamReader> CreateFileReader(
+      const std::string& file_name,
+      int64_t initial_offset,
+      const base::Time& expected_modification_time) = 0;
+  virtual void WriteFile(const std::string& file_name,
+                         const char* buf,
+                         size_t buf_size,
+                         base::Time* modification_time) = 0;
+  // Adjust a file's last modified time by |delta|.
+  virtual void TouchFile(const std::string& file_name,
+                         base::TimeDelta delta) = 0;
+  virtual void EnsureFileTaskFinished() {}
+
+  base::Time test_file_modification_time() const {
+    return test_file_modification_time_;
+  }
+
+  void WriteTestFile() {
+    WriteFile(kTestFileName.data(), kTestData.data(), kTestData.size(),
+              &test_file_modification_time_);
+  }
+
+  static void NeverCalled(int unused) { ADD_FAILURE(); }
+
+ private:
+  base::test::SingleThreadTaskEnvironment task_environment_{
+      base::test::SingleThreadTaskEnvironment::MainThreadType::IO};
+  base::Time test_file_modification_time_;
+};
+
+template <class SubClass>
+class FileStreamReaderTypedTest : public SubClass {
+ public:
+  void SetUp() override {
+    SubClass::SetUp();
+    this->WriteTestFile();
+  }
+};
+
+TYPED_TEST_SUITE_P(FileStreamReaderTypedTest);
+
+TYPED_TEST_P(FileStreamReaderTypedTest, NonExistent) {
+  const char kFileName[] = "nonexistent";
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(kFileName, 0, base::Time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, 10, &result);
+  ASSERT_EQ(net::ERR_FILE_NOT_FOUND, result);
+  ASSERT_EQ(0U, data.size());
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, Empty) {
+  const char kFileName[] = "empty";
+  this->WriteFile(kFileName, nullptr, 0, nullptr);
+
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(kFileName, 0, base::Time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, 10, &result);
+  ASSERT_EQ(net::OK, result);
+  ASSERT_EQ(0U, data.size());
+
+  net::TestInt64CompletionCallback callback;
+  int64_t length_result = reader->GetLength(callback.callback());
+  if (length_result == net::ERR_IO_PENDING)
+    length_result = callback.WaitForResult();
+  ASSERT_EQ(0, result);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, GetLengthNormal) {
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  net::TestInt64CompletionCallback callback;
+  int64_t result = reader->GetLength(callback.callback());
+  if (result == net::ERR_IO_PENDING)
+    result = callback.WaitForResult();
+  ASSERT_EQ(static_cast<int64_t>(this->kTestData.size()), result);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, GetLengthAfterModified) {
+  this->TouchFile(this->kTestFileName.data(), base::TimeDelta::FromSeconds(10));
+
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  net::TestInt64CompletionCallback callback1;
+  int64_t result = reader->GetLength(callback1.callback());
+  if (result == net::ERR_IO_PENDING)
+    result = callback1.WaitForResult();
+  ASSERT_EQ(net::ERR_UPLOAD_FILE_CHANGED, result);
+
+  // With nullptr expected modification time this should work.
+  reader = this->CreateFileReader(this->kTestFileName.data(), 0, base::Time());
+  net::TestInt64CompletionCallback callback2;
+  result = reader->GetLength(callback2.callback());
+  if (result == net::ERR_IO_PENDING)
+    result = callback2.WaitForResult();
+  ASSERT_EQ(static_cast<int64_t>(this->kTestData.size()), result);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, GetLengthWithOffset) {
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(this->kTestFileName.data(), 3, base::Time()));
+  net::TestInt64CompletionCallback callback;
+  int64_t result = reader->GetLength(callback.callback());
+  if (result == net::ERR_IO_PENDING)
+    result = callback.WaitForResult();
+  // Initial offset does not affect the result of GetLength.
+  ASSERT_EQ(static_cast<int64_t>(this->kTestData.size()), result);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadNormal) {
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::OK, result);
+  ASSERT_EQ(this->kTestData, data);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadAfterModified) {
+  // Touch file so that the file's modification time becomes different
+  // from what we expect. Note that the resolution on some filesystems
+  // is 1s so we can't test with deltas less than that.
+  this->TouchFile(this->kTestFileName.data(), base::TimeDelta::FromSeconds(-1));
+
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::ERR_UPLOAD_FILE_CHANGED, result);
+  ASSERT_EQ(0U, data.size());
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadAfterModifiedLessThanThreshold) {
+  // Due to precision loss converting int64_t->double->int64_t (e.g. through
+  // Blink) the expected/actual time may vary by microseconds. With
+  // modification time delta < 10us this should work.
+  this->TouchFile(this->kTestFileName.data(),
+                  base::TimeDelta::FromMicroseconds(1));
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  int result = 0;
+  std::string data;
+
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::OK, result);
+  ASSERT_EQ(this->kTestData, data);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadAfterModifiedWithMatchingTimes) {
+  this->TouchFile(this->kTestFileName.data(), base::TimeDelta());
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), 0, this->test_file_modification_time()));
+  int result = 0;
+  std::string data;
+
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::OK, result);
+  ASSERT_EQ(this->kTestData, data);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadAfterModifiedWithoutExpectedTime) {
+  this->TouchFile(this->kTestFileName.data(), base::TimeDelta::FromSeconds(-1));
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(this->kTestFileName.data(), 0, base::Time()));
+  int result = 0;
+  std::string data;
+
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::OK, result);
+  ASSERT_EQ(this->kTestData, data);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadWithOffset) {
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(this->kTestFileName.data(), 3, base::Time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, this->kTestData.size(), &result);
+  ASSERT_EQ(net::OK, result);
+
+  ASSERT_EQ(this->kTestData.substr(3), data);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadWithNegativeOffset) {
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(this->kTestFileName.data(), -1, base::Time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, 1, &result);
+  ASSERT_EQ(net::ERR_INVALID_ARGUMENT, result);
+  ASSERT_EQ(data.size(), 0u);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, ReadWithOffsetLargerThanFile) {
+  std::unique_ptr<FileStreamReader> reader(this->CreateFileReader(
+      this->kTestFileName.data(), this->kTestData.size() + 1, base::Time()));
+  int result = 0;
+  std::string data;
+  ReadFromReader(reader.get(), &data, 1, &result);
+  ASSERT_EQ(data.size(), 0u);
+  ASSERT_EQ(net::OK, result);
+}
+
+TYPED_TEST_P(FileStreamReaderTypedTest, DeleteWithUnfinishedRead) {
+  std::unique_ptr<FileStreamReader> reader(
+      this->CreateFileReader(this->kTestFileName.data(), 0, base::Time()));
+
+  net::TestCompletionCallback callback;
+  scoped_refptr<net::IOBufferWithSize> buf =
+      base::MakeRefCounted<net::IOBufferWithSize>(this->kTestData.size());
+  int rv = reader->Read(buf.get(), buf->size(),
+                        base::BindOnce(&FileStreamReaderTest::NeverCalled));
+  if (rv < 0)
+    ASSERT_EQ(rv, net::ERR_IO_PENDING);
+
+  // Delete immediately.
+  // Should not crash; nor should NeverCalled be callback.
+  reader = nullptr;
+  this->EnsureFileTaskFinished();
+}
+
+REGISTER_TYPED_TEST_SUITE_P(FileStreamReaderTypedTest,
+                            NonExistent,
+                            Empty,
+                            GetLengthNormal,
+                            GetLengthAfterModified,
+                            GetLengthWithOffset,
+                            ReadNormal,
+                            ReadAfterModified,
+                            ReadAfterModifiedLessThanThreshold,
+                            ReadAfterModifiedWithMatchingTimes,
+                            ReadAfterModifiedWithoutExpectedTime,
+                            ReadWithOffset,
+                            ReadWithNegativeOffset,
+                            ReadWithOffsetLargerThanFile,
+                            DeleteWithUnfinishedRead);
+
+}  // namespace storage
+
+#endif  // STORAGE_BROWSER_FILE_SYSTEM_FILE_STREAM_READER_TEST_H_