diff --git a/mobly/controllers/android_device_lib/adb.py b/mobly/controllers/android_device_lib/adb.py
index 90dcd0b..95d1261 100644
--- a/mobly/controllers/android_device_lib/adb.py
+++ b/mobly/controllers/android_device_lib/adb.py
@@ -203,6 +203,7 @@ class AdbProxy(object):
             stderr=subprocess.PIPE,
             shell=shell,
             bufsize=1)
+        out = '[elided, processed via handler]'
         try:
             while proc.poll() is None:
                 line = proc.stdout.readline()
@@ -211,16 +212,19 @@ class AdbProxy(object):
                 else:
                     break
         finally:
-            (_, err) = proc.communicate()
+            (unexpected_out, err) = proc.communicate()
+            if unexpected_out:
+                out = '[unexpected stdout] %s' % unexpected_out
+                for line in unexpected_out.splitlines():
+                    handler(line)
+
         ret = proc.returncode
+        logging.debug('cmd: %s, stdout: %s, stderr: %s, ret: %s',
+                      cli_cmd_to_string(args), out, err, ret)
         if ret == 0:
             return err
         else:
-            raise AdbError(
-                cmd=args,
-                stdout='[elided, processed via handler]',
-                stderr=err,
-                ret_code=ret)
+            raise AdbError(cmd=args, stdout=out, stderr=err, ret_code=ret)
 
     def _construct_adb_cmd(self, raw_name, args, shell):
         """Constructs an adb command with arguments for a subprocess call.
diff --git a/mobly/controllers/android_device_lib/snippet_client.py b/mobly/controllers/android_device_lib/snippet_client.py
index e3e835d..03674ff 100644
--- a/mobly/controllers/android_device_lib/snippet_client.py
+++ b/mobly/controllers/android_device_lib/snippet_client.py
@@ -125,8 +125,7 @@ class SnippetClient(jsonrpc_client_base.JsonRpcClientBase):
 
         # Yaaay! We're done!
         self.log.debug('Snippet %s started after %.1fs on host port %s',
-                       self.package,
-                       time.time() - start_time, self.host_port)
+                       self.package, time.time() - start_time, self.host_port)
 
     def restore_app_connection(self, port=None):
         """Restores the app after device got reconnected.
@@ -151,12 +150,13 @@ class SnippetClient(jsonrpc_client_base.JsonRpcClientBase):
         try:
             self.connect()
         except:
-            # Failed to connect to app, something went wrong.
+            # Log the original error and raise AppRestoreConnectionError.
+            self.log.exception('Failed to re-connect to app.')
             raise jsonrpc_client_base.AppRestoreConnectionError(
-                self._ad(
-                    'Failed to restore app connection for %s at host port %s, '
-                    'device port %s'), self.package, self.host_port,
-                self.device_port)
+                self._ad,
+                ('Failed to restore app connection for %s at host port %s, '
+                 'device port %s') % (self.package, self.host_port,
+                                      self.device_port))
 
         # Because the previous connection was lost, update self._proc
         self._proc = None

diff --git a/tests/mobly/controllers/android_device_lib/adb_test.py b/tests/mobly/controllers/android_device_lib/adb_test.py
index 1c75a9d..8dec8aa 100755
--- a/tests/mobly/controllers/android_device_lib/adb_test.py
+++ b/tests/mobly/controllers/android_device_lib/adb_test.py
@@ -76,8 +76,7 @@ class AdbTest(unittest.TestCase):
         mock_popen.return_value.stdout.readline.side_effect = ['']
 
         mock_proc.communicate = mock.Mock(
-            return_value=(MOCK_DEFAULT_STDOUT.encode('utf-8'),
-                          MOCK_DEFAULT_STDERR.encode('utf-8')))
+            return_value=('', MOCK_DEFAULT_STDERR.encode('utf-8')))
         mock_proc.returncode = 0
         return mock_popen
 
@@ -150,6 +149,57 @@ class AdbTest(unittest.TestCase):
         mock_handler.assert_any_call('1')
         mock_handler.assert_any_call('2')
 
+    @mock.patch('mobly.controllers.android_device_lib.adb.subprocess.Popen')
+    def test_execute_and_process_stdout_reads_unexpected_stdout(
+            self, mock_popen):
+        unexpected_stdout = MOCK_DEFAULT_STDOUT.encode('utf-8')
+
+        self._mock_execute_and_process_stdout_process(mock_popen)
+        mock_handler = mock.MagicMock()
+        mock_popen.return_value.communicate = mock.Mock(
+            return_value=(unexpected_stdout, MOCK_DEFAULT_STDERR.encode(
+                'utf-8')))
+
+        err = adb.AdbProxy()._execute_and_process_stdout(
+            ['fake_cmd'], shell=False, handler=mock_handler)
+        self.assertEqual(mock_handler.call_count, 1)
+        mock_handler.assert_called_with(unexpected_stdout)
+
+    @mock.patch('mobly.controllers.android_device_lib.adb.subprocess.Popen')
+    @mock.patch('logging.debug')
+    def test_execute_and_process_stdout_logs_cmd(self, mock_debug_logger,
+                                                 mock_popen):
+        raw_expected_stdout = ''
+        expected_stdout = '[elided, processed via handler]'
+        expected_stderr = MOCK_DEFAULT_STDERR.encode('utf-8')
+        self._mock_execute_and_process_stdout_process(mock_popen)
+        mock_popen.return_value.communicate = mock.Mock(
+            return_value=(raw_expected_stdout, expected_stderr))
+
+        err = adb.AdbProxy()._execute_and_process_stdout(
+            ['fake_cmd'], shell=False, handler=mock.MagicMock())
+        mock_debug_logger.assert_called_with(
+            'cmd: %s, stdout: %s, stderr: %s, ret: %s', 'fake_cmd',
+            expected_stdout, expected_stderr, 0)
+
+    @mock.patch('mobly.controllers.android_device_lib.adb.subprocess.Popen')
+    @mock.patch('logging.debug')
+    def test_execute_and_process_stdout_logs_cmd_with_unexpected_stdout(
+            self, mock_debug_logger, mock_popen):
+        raw_expected_stdout = MOCK_DEFAULT_STDOUT.encode('utf-8')
+        expected_stdout = '[unexpected stdout] %s' % raw_expected_stdout
+        expected_stderr = MOCK_DEFAULT_STDERR.encode('utf-8')
+
+        self._mock_execute_and_process_stdout_process(mock_popen)
+        mock_popen.return_value.communicate = mock.Mock(
+            return_value=(raw_expected_stdout, expected_stderr))
+
+        err = adb.AdbProxy()._execute_and_process_stdout(
+            ['fake_cmd'], shell=False, handler=mock.MagicMock())
+        mock_debug_logger.assert_called_with(
+            'cmd: %s, stdout: %s, stderr: %s, ret: %s', 'fake_cmd',
+            expected_stdout, expected_stderr, 0)
+
     @mock.patch('mobly.controllers.android_device_lib.adb.subprocess.Popen')
     def test_execute_and_process_stdout_when_cmd_exits(self, mock_popen):
         self._mock_execute_and_process_stdout_process(mock_popen)
diff --git a/tests/mobly/controllers/android_device_lib/snippet_client_test.py b/tests/mobly/controllers/android_device_lib/snippet_client_test.py
index 2c875d8..d964ae3 100755
--- a/tests/mobly/controllers/android_device_lib/snippet_client_test.py
+++ b/tests/mobly/controllers/android_device_lib/snippet_client_test.py
@@ -166,6 +166,15 @@ class SnippetClientTest(jsonrpc_client_test_base.JsonRpcClientTestBase):
         self.assertEqual(789, callback._event_client.host_port)
         self.assertEqual(456, callback._event_client.device_port)
 
+        # if unable to reconnect for any reason, a
+        # jsonrpc_client_base.AppRestoreConnectionError is raised.
+        mock_create_connection.side_effect = IOError('socket timed out')
+        with self.assertRaisesRegex(
+                jsonrpc_client_base.AppRestoreConnectionError,
+            ('Failed to restore app connection for %s at host port %s, '
+             'device port %s') % (MOCK_PACKAGE_NAME, 789, 456)):
+            client.restore_app_connection()
+
     @mock.patch('socket.create_connection')
     @mock.patch('mobly.controllers.android_device_lib.snippet_client.'
                 'utils.start_standing_subprocess')

`_execute_and_process_stdout` should log cmd
tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_logs_cmd tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_logs_cmd_with_unexpected_stdout tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_reads_unexpected_stdout tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_restore_event_client
tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_cli_cmd_to_string tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_one_arg_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_one_arg_command_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_one_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_serial tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_serial_with_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_auto_quotes tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_one_arg_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_one_arg_command_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_one_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_serial tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_shell_true_with_serial_with_list tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_construct_adb_cmd_with_special_characters tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_adb_cmd tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_adb_cmd_formats_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_adb_cmd_formats_command_with_shell_true tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_adb_cmd_with_shell_true tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_adb_cmd_with_stderr_pipe tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_cmd_error_no_timeout tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_cmd_no_timeout_success tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_cmd_timed_out tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_cmd_with_negative_timeout_value tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_exec_cmd_with_timeout_success tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_adb_and_process_stdout_formats_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_raises_adb_error tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_reads_stdout tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_returns_stderr tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_when_cmd_eof tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_when_cmd_exits tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_execute_and_process_stdout_when_handler_crash tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_forward tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_has_shell_command_called_correctly tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_has_shell_command_with_existing_command tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_has_shell_command_with_missing_command_on_newer_devices tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_has_shell_command_with_missing_command_on_older_devices tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_with_handler tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_with_handler_with_options tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_with_handler_with_runner tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_with_options tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_with_runner tests/mobly/controllers/android_device_lib/adb_test.py::AdbTest::test_instrument_without_parameters tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_check_app_installed_fail_app_not_installed tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_check_app_installed_fail_not_instrumented tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_check_app_installed_fail_target_not_installed tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_check_app_installed_normal tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_and_connect tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_and_connect_header_junk tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_and_connect_no_valid_line tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_and_connect_persistent_session tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_and_connect_unknown_protocol tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_app_crash tests/mobly/controllers/android_device_lib/snippet_client_test.py::SnippetClientTest::test_snippet_start_event_client