[net] Subtract timestamps to determine if uploading file changed.

net/base/upload_file_element_reader_unittest.cc

 // Copyright (c) 2012 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 "net/base/upload_file_element_reader.h"
 
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/run_loop.h"
@@ skipping 203 matching lines @@
       new UploadFileElementReader(base::MessageLoopProxy::current().get(),
                                   temp_file_path_,
                                   0,
                                   kuint64max,
                                   expected_modification_time));
   TestCompletionCallback init_callback;
   ASSERT_EQ(ERR_IO_PENDING, reader_->Init(init_callback.callback()));
   EXPECT_EQ(ERR_UPLOAD_FILE_CHANGED, init_callback.WaitForResult());
 }
 
+TEST_F(UploadFileElementReaderTest, InexactExpectedTimeStamp) {
+  base::File::Info info;
+  ASSERT_TRUE(base::GetFileInfo(temp_file_path_, &info));
+
+  const base::Time expected_modification_time =
+      info.last_modified - base::TimeDelta::FromMilliseconds(900);
+  reader_.reset(new UploadFileElementReader(
+      base::MessageLoopProxy::current().get(), temp_file_path_, 0, kuint64max,
+      expected_modification_time));

[mmenke, 2015/02/02 15:34:21]

nit:  While you're here, should format the identical line in the above and below
tests to match this one, to make it clearer the tests are doing the exact same
thing here.

+  TestCompletionCallback init_callback;
+  ASSERT_EQ(ERR_IO_PENDING, reader_->Init(init_callback.callback()));
+  EXPECT_EQ(OK, init_callback.WaitForResult());
+}
+
 TEST_F(UploadFileElementReaderTest, WrongPath) {
   const base::FilePath wrong_path(FILE_PATH_LITERAL("wrong_path"));
   reader_.reset(
       new UploadFileElementReader(base::MessageLoopProxy::current().get(),
                                   wrong_path,
                                   0,
                                   kuint64max,
                                   base::Time()));
   TestCompletionCallback init_callback;
   ASSERT_EQ(ERR_IO_PENDING, reader_->Init(init_callback.callback()));
   EXPECT_EQ(ERR_FILE_NOT_FOUND, init_callback.WaitForResult());
 }
 
 }  // namespace net