Add run_with_dummy_home.py to speed up browser tests by 5x on gLinux.
This is useful for isolating tests from the insanity that might reside
in $HOME. For example, certain NSS configurations can cause process
startup to be extremely slow. Preliminary numbers indicate a 5.4x
speedup when running all content_browsertests with 20 parallel jobs on
gLinux.
Bug: 913027
Change-Id: I87097223aca2e121b557c2a982ec0cbc9cd2321c
Reviewed-on: https://chromium-review.googlesource.com/c/1368589
Reviewed-by: Dirk Pranke <[email protected]>
Cr-Commit-Position: refs/heads/master@{#615334}diff --git a/testing/run_with_dummy_home.py b/testing/run_with_dummy_home.py
new file mode 100755
index 0000000..3d28e06
--- /dev/null
+++ b/testing/run_with_dummy_home.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+# Copyright 2018 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.
+
+"""Usage: run_with_dummy_home.py <command>
+
+Helper for running a test with a dummy $HOME, populated with just enough for
+tests to run and pass. Useful for isolating tests from the real $HOME, which
+can contain config files that negatively affect test performance.
+"""
+
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+
+
+def _set_up_dummy_home(original_home, dummy_home):
+ """Sets up a dummy $HOME that Chromium tests can run in.
+
+ Files are copied, while directories are symlinked.
+ """
+ for filename in ['.Xauthority']:
+ original_path = os.path.join(original_home, filename)
+ if not os.path.exists(original_path):
+ continue
+ shutil.copyfile(original_path, os.path.join(dummy_home, filename))
+
+ # Prevent fontconfig etc. from reconstructing the cache and symlink rr
+ # trace directory.
+ for dirpath in [['.cache'], ['.local', 'share', 'rr'], ['.vpython'],
+ ['.vpython_cipd_cache'], ['.vpython-root']]:
+ original_path = os.path.join(original_home, *dirpath)
+ if not os.path.exists(original_path):
+ continue
+ dummy_parent_path = os.path.join(dummy_home, *dirpath[:-1])
+ if not os.path.isdir(dummy_parent_path):
+ os.makedirs(dummy_parent_path)
+ os.symlink(original_path, os.path.join(dummy_home, *dirpath))
+
+
+def main():
+ try:
+ dummy_home = tempfile.mkdtemp()
+ print 'Creating dummy home in %s' % dummy_home
+
+ original_home = os.environ['HOME']
+ os.environ['HOME'] = dummy_home
+ _set_up_dummy_home(original_home, dummy_home)
+
+ return subprocess.call(sys.argv[1:])
+ finally:
+ shutil.rmtree(dummy_home)
+
+
+if __name__ == '__main__':
+ sys.exit(main())
