diff --git a/tests/daemon/__init__.py b/tests/daemon/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/daemon/test_service.py b/tests/daemon/test_service.py
new file mode 100644
index 0000000..75595a7
--- /dev/null
+++ b/tests/daemon/test_service.py
@@ -0,0 +1,33 @@
+import mock
+import unittest
+
+from ubuntucleaner.daemon.service import DaemonService
+
+
+class TestDaemonService(unittest.TestCase):
+
+    def test_get_cmd_pipe_no_process(self):
+        with mock.patch.object(DaemonService, '__init__') as mocked_service:
+            mocked_service.return_value = None
+
+            mocked_service = DaemonService()
+            assert mocked_service.get_cmd_pipe() == ('', 'None')
+
+    def test_get_cmd_pipe_terminaled_none(self):
+        with mock.patch.object(DaemonService, '__init__') as mocked_service:
+            mocked_service.return_value = None
+
+            mocked_service = DaemonService()
+            mocked_service.p = mock.Mock()
+            mocked_service.p.poll.return_value = None
+            mocked_service.p.stdout.readline.return_value = "test"
+            assert mocked_service.get_cmd_pipe() == ('test', 'None')
+
+    def test_get_cmd_pipe_terminaled(self):
+        with mock.patch.object(DaemonService, '__init__') as mocked_service:
+            mocked_service.return_value = None
+
+            mocked_service = DaemonService()
+            mocked_service.p = mock.Mock()
+            mocked_service.p.stdout.readlines.return_value = [b'test', b'stdout']
+            assert mocked_service.get_cmd_pipe()[0] == b'test stdout'
diff --git a/ubuntucleaner/daemon/service.py b/ubuntucleaner/daemon/service.py
index 0213a88..44724bb 100644
--- a/ubuntucleaner/daemon/service.py
+++ b/ubuntucleaner/daemon/service.py
@@ -62,7 +62,7 @@ def get_cmd_pipe(self):
                 except:
                     return '', 'None'
             else:
-                strings, returncode = ''.join(self.p.stdout.readlines()), str(terminaled)
+                strings, returncode = b' '.join(self.p.stdout.readlines()), str(terminaled)
                 self.p = None
                 return strings, returncode
         else: