diff --git a/tests/cmd/__init__.py b/tests/cmd/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tests/cmd/__init__.py
diff --git a/tests/cmd/test_cloner.py b/tests/cmd/test_cloner.py
new file mode 100644
index 0000000..9cbb5b8
--- /dev/null
+++ b/tests/cmd/test_cloner.py
@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import logging
+import os
+
+import testtools
+import zuul.cmd.cloner
+
+logging.basicConfig(level=logging.DEBUG,
+                    format='%(asctime)s %(name)-32s '
+                    '%(levelname)-8s %(message)s')
+
+
+class TestClonerCmdArguments(testtools.TestCase):
+
+    def setUp(self):
+        super(TestClonerCmdArguments, self).setUp()
+        self.app = zuul.cmd.cloner.Cloner()
+
+    def test_default_cache_dir_empty(self):
+        self.app.parse_arguments(['base', 'repo'])
+        self.assertEqual(None, self.app.args.cache_dir)
+
+    def test_default_cache_dir_environ(self):
+        try:
+            os.environ['ZUUL_CACHE_DIR'] = 'fromenviron'
+            self.app.parse_arguments(['base', 'repo'])
+            self.assertEqual('fromenviron', self.app.args.cache_dir)
+        finally:
+            del os.environ['ZUUL_CACHE_DIR']
+
+    def test_default_cache_dir_override_environ(self):
+        try:
+            os.environ['ZUUL_CACHE_DIR'] = 'fromenviron'
+            self.app.parse_arguments(['--cache-dir', 'argument',
+                                      'base', 'repo'])
+            self.assertEqual('argument', self.app.args.cache_dir)
+        finally:
+            del os.environ['ZUUL_CACHE_DIR']
+
+    def test_default_cache_dir_argument(self):
+        self.app.parse_arguments(['--cache-dir', 'argument',
+                                  'base', 'repo'])
+        self.assertEqual('argument', self.app.args.cache_dir)
diff --git a/zuul/cmd/cloner.py b/zuul/cmd/cloner.py
index 30401d6..c616aa1 100755
--- a/zuul/cmd/cloner.py
+++ b/zuul/cmd/cloner.py
@@ -33,7 +33,7 @@
 class Cloner(zuul.cmd.ZuulApp):
     log = logging.getLogger("zuul.Cloner")
 
-    def parse_arguments(self):
+    def parse_arguments(self, args=sys.argv[1:]):
         """Parse command line arguments and returns argparse structure"""
         parser = argparse.ArgumentParser(
             description='Zuul Project Gating System Cloner.')
@@ -90,7 +90,7 @@
                 default=os.environ.get(env_name)
             )
 
-        args = parser.parse_args()
+        args = parser.parse_args(args)
         # Validate ZUUL_* arguments. If ref is provided then URL is required.
         zuul_args = [zuul_opt for zuul_opt, val in vars(args).items()
                      if zuul_opt.startswith('zuul') and val is not None]