Reduce flakiness in IvfFileWriter tests.

webrtc/modules/video_coding/utility/ivf_file_writer_unittest.cc

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/modules/video_coding/utility/ivf_file_writer.h"
 
 #include <memory>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "webrtc/base/logging.h"
+#include "webrtc/base/thread.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
 #include "webrtc/test/testsupport/fileutils.h"
 
 namespace webrtc {
 
 namespace {
 static const int kHeaderSize = 32;
 static const int kFrameHeaderSize = 12;
 static uint8_t dummy_payload[4] = {0, 1, 2, 3};
+static const int kMaxFileRetries = 5;
 }  // namespace
 
 class IvfFileWriterTest : public ::testing::Test {
  protected:
   void SetUp() override {
     const int64_t start_id =
         reinterpret_cast<int64_t>(this) ^ rtc::TimeMicros();
     int64_t id = start_id;
     do {
       std::ostringstream oss;
       oss << test::OutputPath() << "ivf_test_file_" << id++ << ".ivf";
       file_name_ = oss.str();
-    } while (id < start_id + 100 && FileExists());
+    } while (id < start_id + 100 && FileExists(false));
     ASSERT_LT(id, start_id + 100);
   }
 
   bool WriteDummyTestFrames(int width,
                             int height,
                             int num_frames,
                             bool use_capture_tims_ms) {
     EncodedImage frame;
     frame._buffer = dummy_payload;
     frame._encodedWidth = width;
@@ skipping 64 matching lines @@
     EXPECT_TRUE(
         WriteDummyTestFrames(kWidth, kHeight, kNumFrames, use_capture_tims_ms));
     EXPECT_TRUE(file_writer_->Close());
 
     std::unique_ptr<FileWrapper> out_file(FileWrapper::Create());
     ASSERT_EQ(0, out_file->OpenFile(file_name_.c_str(), true));
     VerifyIvfHeader(out_file.get(), fourcc, kWidth, kHeight, kNumFrames,
                     use_capture_tims_ms);
     VerifyDummyTestFrames(out_file.get(), kNumFrames);
 
+    out_file->Flush();
     EXPECT_EQ(0, out_file->CloseFile());
-    EXPECT_EQ(0, remove(file_name_.c_str()));
+
+    bool file_removed = false;
+    for (int i = 0; i < kMaxFileRetries; ++i) {
+      file_removed = remove(file_name_.c_str()) == 0;
+      if (file_removed)
+        break;
+
+      // Couldn't remove file for some reason, wait a sec and try again.
+      rtc::Thread::SleepMs(1000);
+    }
+    EXPECT_TRUE(file_removed);
   }
 
-  bool FileExists() {
-    std::unique_ptr<FileWrapper> file_wrapper(FileWrapper::Create());
-    return file_wrapper->OpenFile(file_name_.c_str(), true) == 0;
+  // Check whether file exists or not, and if it does not meet expectation,
+  // wait a bit and check again, up to kMaxFileRetries times. This is an ugly
+  // hack to avoid flakiness on certain operating systems where antivirus
+  // software may unexpectedly lock files and keep them from disappearing or
+  // being reused.
+  bool FileExists(bool expected) {
+    bool file_exists = expected;
+    std::unique_ptr<FileWrapper> file_wrapper;
+    int iterations = 0;
+    do {
+      if (file_wrapper.get() != nullptr)
+        rtc::Thread::SleepMs(1000);
+      file_wrapper.reset(FileWrapper::Create());
+      file_exists = file_wrapper->OpenFile(file_name_.c_str(), true) == 0;
+      file_wrapper->CloseFile();
+    } while (file_exists != expected && ++iterations < kMaxFileRetries);
+    return file_exists;
   }
 
   std::string file_name_;
   std::unique_ptr<IvfFileWriter> file_writer_;
 };
 
 TEST_F(IvfFileWriterTest, RemovesUnusedFile) {
   file_writer_ = IvfFileWriter::Open(file_name_, kVideoCodecVP8);
   ASSERT_TRUE(file_writer_.get() != nullptr);
-  EXPECT_TRUE(FileExists());
+  EXPECT_TRUE(FileExists(true));
   EXPECT_TRUE(file_writer_->Close());
-  EXPECT_FALSE(FileExists());
+  EXPECT_FALSE(FileExists(false));
   EXPECT_FALSE(file_writer_->Close());  // Can't close twice.
 }
 
 TEST_F(IvfFileWriterTest, WritesBasicVP8FileNtpTimestamp) {
   const uint8_t fourcc[4] = {'V', 'P', '8', '0'};
   RunBasicFileStructureTest(kVideoCodecVP8, fourcc, false);
 }
 
 TEST_F(IvfFileWriterTest, WritesBasicVP8FileMsTimestamp) {
   const uint8_t fourcc[4] = {'V', 'P', '8', '0'};
@@ skipping 14 matching lines @@
   const uint8_t fourcc[4] = {'H', '2', '6', '4'};
   RunBasicFileStructureTest(kVideoCodecH264, fourcc, false);
 }
 
 TEST_F(IvfFileWriterTest, WritesBasicH264FileMsTimestamp) {
   const uint8_t fourcc[4] = {'H', '2', '6', '4'};
   RunBasicFileStructureTest(kVideoCodecH264, fourcc, true);
 }
 
 }  // namespace webrtc