adb: make the test_pull_dir test actually test something.

Change-Id: I8b525377557528d5bc70c44d587891fad9f739bd
diff --git a/adb/test_device.py b/adb/test_device.py
index 8d75468..955b67a 100644
--- a/adb/test_device.py
+++ b/adb/test_device.py
@@ -819,7 +819,10 @@
             self.device.pull(remote=self.DEVICE_TEMP_DIR, local=host_dir)
 
             for temp_file in temp_files:
-                host_path = os.path.join(host_dir, temp_file.base_name)
+                host_path = os.path.join(
+                    host_dir, posixpath.basename(self.DEVICE_TEMP_DIR),
+                    temp_file.base_name)
+                self._verify_local(temp_file.checksum, host_path)
 
             self.device.shell(['rm', '-rf', self.DEVICE_TEMP_DIR])
         finally: