@@ -31,6 +31,7 @@ const (

 	unitTestImageIDShort     = "83599e29c455"

 	unitTestNetworkBridge    = "testdockbr0"

 	unitTestStoreBase        = "/var/lib/docker/unit-tests"

+	unitTestDockerTmpdir     = "/var/lib/docker/tmp"

 	testDaemonAddr           = "127.0.0.1:4270"

 	testDaemonProto          = "tcp"

 	testDaemonHttpsProto     = "tcp"

@@ -90,6 +91,7 @@ func init() {

 	// To test other drivers, we need a dedicated driver validation suite.

 	os.Setenv("DOCKER_DRIVER", "vfs")

 	os.Setenv("TEST", "1")

+	os.Setenv("DOCKER_TMPDIR", unitTestDockerTmpdir)

 	// Hack to run sys init during unit testing

 	if selfPath := utils.SelfPath(); strings.Contains(selfPath, ".dockerinit") {