Disable compression in AdbPull()

Compression makes adb pull slower, enough to make the /vendor pull
in vts_vndk_dependency_test time out on some devices.

Commit I9ed6f37bc55b1d55ae7c0c29a70a0e79b91ff683 updates the default
for adb pull, but VTS may run with an older version. Setting the
ADB_COMPRESSION environment variable to 0 will disable compression
for all versions supporting it, and does no harm otherwise.

This change takes vts_vndk_dependency_test from 396 to 181 seconds
on my device, allowing it to finish within the 6-minute deadline.

Change-Id: Ic0a5e5e5ac07a78f593619487c66376ab1a417df

1 files changed, 4 insertions, 1 deletions

diff --git a/utils.py b/utils.py
index 5fae388..8bf00f3 100644
--- a/utils.py
+++ b/utils.py
@@ -32,7 +32,10 @@ class AndroidDevice(object):
 
     def AdbPull(self, src, dst):
         cmd = ["adb", "-s", self._serial_number, "pull", src, dst]
-        subprocess.check_call(cmd, shell=False, stdin=subprocess.PIPE,
+        env = os.environ.copy()
+        if "ADB_COMPRESSION" not in env:
+            env["ADB_COMPRESSION"] = "0"
+        subprocess.check_call(cmd, shell=False, env=env, stdin=subprocess.PIPE,
                               stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 
     def Execute(self, *args):