Take 2: Force python test server output to be unbuffered, so it doesn't mix with gtest output

In browser tests that use a local python server, the python output in
the test logs sometimes overlaps with gtest output, resulting in gtest
falsely detecting passing tests as incomplete. This is a result of
python's default use of buffered output, which gets written to the log
file out of order.

This patch forces the python process for local test servers to use
unbuffered mode via the -u switch. This way, by the time gtest is ready
to log a passing test, all testserver output is already written to the
log file.

BUG=147368
TEST= See sync integration test output when it is redirected to a log file, and make sure there are no false negatives.

Review URL: https://chromiumcodereview.appspot.com/10907162

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@156361 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 15 insertions, 6 deletions

diff --git a/net/test/python_utils.cc b/net/test/python_utils.cc
index 0eec816..82d0c5c 100644
--- a/net/test/python_utils.cc
+++ b/net/test/python_utils.cc
@@ -5,6 +5,7 @@
 #include "net/test/python_utils.h"
 
 #include "base/base_paths.h"
+#include "base/command_line.h"
 #include "base/environment.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ -103,15 +104,23 @@ bool GetPyProtoPath(FilePath* dir) {
   return true;
 }
 
-bool GetPythonRunTime(FilePath* dir) {
+bool GetPythonCommand(CommandLine* python_cmd) {
+  DCHECK(python_cmd);
+  FilePath dir;
 #if defined(OS_WIN)
-  if (!PathService::Get(base::DIR_SOURCE_ROOT, dir))
+  if (!PathService::Get(base::DIR_SOURCE_ROOT, &dir))
     return false;
-  *dir = dir->Append(FILE_PATH_LITERAL("third_party"))
-      .Append(FILE_PATH_LITERAL("python_26"))
-      .Append(FILE_PATH_LITERAL("python.exe"));
+  dir = dir.Append(FILE_PATH_LITERAL("third_party"))
+           .Append(FILE_PATH_LITERAL("python_26"))
+           .Append(FILE_PATH_LITERAL("python.exe"));
 #elif defined(OS_POSIX)
-  *dir = FilePath("python");
+  dir = FilePath("python");
 #endif
+  python_cmd->SetProgram(dir);
+
+  // Launch python in unbuffered mode, so that python output doesn't mix with
+  // gtest output in buildbot log files. See http://crbug.com/147368.
+  python_cmd->AppendArg("-u");
+
   return true;
 }