diff --git a/gnes/cli/parser.py b/gnes/cli/parser.py
index ab08d760..e3a2e3ae 100644
--- a/gnes/cli/parser.py
+++ b/gnes/cli/parser.py
@@ -154,6 +154,7 @@ def set_preprocessor_service_parser(parser=None):
         parser = set_base_parser()
     from pkg_resources import resource_stream
     set_loadable_service_parser(parser)
+    parser.get_default('yaml_path').close()
     parser.set_defaults(yaml_path=resource_stream(
         'gnes', '/'.join(('resources', 'config', 'preprocessor', 'default.yml'))))
 
@@ -166,6 +167,7 @@ def set_router_service_parser(parser=None):
     if not parser:
         parser = set_base_parser()
     set_loadable_service_parser(parser)
+    parser.get_default('yaml_path').close()
     parser.set_defaults(yaml_path=resource_stream(
         'gnes', '/'.join(('resources', 'config', 'router', 'default.yml'))))
 
@@ -180,6 +182,7 @@ def set_indexer_service_parser(parser=None):
     if not parser:
         parser = set_base_parser()
     set_loadable_service_parser(parser)
+    parser.get_default('yaml_path').close()
     parser.set_defaults(yaml_path=resource_stream(
         'gnes', '/'.join(('resources', 'config', 'indexer', 'default.yml'))))
 
diff --git a/tests/test_preprocessor.py b/tests/test_preprocessor.py
index a4ac0a6e..c180ffac 100644
--- a/tests/test_preprocessor.py
+++ b/tests/test_preprocessor.py
@@ -2,6 +2,7 @@
 import unittest
 
 from gnes.cli.parser import set_preprocessor_service_parser, _set_client_parser
+from gnes.composer.base import YamlComposer
 from gnes.proto import gnes_pb2
 from gnes.service.grpc import ZmqClient
 from gnes.service.preprocessor import PreprocessorService
@@ -15,12 +16,18 @@ def setUp(self):
         self.dirname = os.path.dirname(__file__)
 
     def test_preprocessor_service_empty(self):
-        args = set_preprocessor_service_parser().parse_args([])
+        args = set_preprocessor_service_parser().parse_args([
+            '--port_in', str(YamlComposer._get_random_port()),
+            '--port_out', str(YamlComposer._get_random_port())
+        ])
         with PreprocessorService(args):
             pass
 
     def test_preprocessor_service_echo(self):
-        args = set_preprocessor_service_parser().parse_args([])
+        args = set_preprocessor_service_parser().parse_args([
+            '--port_in', str(YamlComposer._get_random_port()),
+            '--port_out', str(YamlComposer._get_random_port())
+        ])
         c_args = _set_client_parser().parse_args([
             '--port_in', str(args.port_out),
             '--port_out', str(args.port_in)
@@ -37,7 +44,10 @@ def test_preprocessor_service_echo(self):
             print(r)
 
     def test_preprocessor_service_realdata(self):
-        args = set_preprocessor_service_parser().parse_args([])
+        args = set_preprocessor_service_parser().parse_args([
+            '--port_in', str(YamlComposer._get_random_port()),
+            '--port_out', str(YamlComposer._get_random_port())
+        ])
         c_args = _set_client_parser().parse_args([
             '--port_in', str(args.port_out),
             '--port_out', str(args.port_in)