diff --git a/os_testr/tests/utils/__init__.py b/os_testr/tests/utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/os_testr/tests/utils/test_colorizer.py b/os_testr/tests/utils/test_colorizer.py
new file mode 100644
index 0000000..fdf96b2
--- /dev/null
+++ b/os_testr/tests/utils/test_colorizer.py
@@ -0,0 +1,76 @@
+# Copyright 2016 Hewlett Packard Enterprise Development LP
+# All Rights Reserved.
+#
+#    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 six
+import sys
+
+from ddt import data
+from ddt import ddt
+from ddt import unpack
+
+from os_testr.tests import base
+from os_testr.utils import colorizer
+
+
+@ddt
+class TestNullColorizer(base.TestCase):
+
+    @data(None, "foo", sys.stdout, )
+    def test_supported_always_true(self, stream):
+        self.assertTrue(colorizer.NullColorizer.supported(stream))
+
+    @data(("foo", "red"), ("foo", "bar"))
+    @unpack
+    def test_write_string_ignore_color(self, text, color):
+        output = six.StringIO()
+        c = colorizer.NullColorizer(output)
+        c.write(text, color)
+        self.assertEqual(text, output.getvalue())
+
+    @data((None, "red"), (None, None))
+    @unpack
+    def test_write_none_exception(self, text, color):
+        c = colorizer.NullColorizer(sys.stdout)
+        self.assertRaises(TypeError, c.write, text, color)
+
+
+@ddt
+class TestAnsiColorizer(base.TestCase):
+
+    def test_supported_false(self):
+        # NOTE(masayukig): This returns False because our unittest env isn't
+        #  interactive
+        self.assertFalse(colorizer.AnsiColorizer.supported(sys.stdout))
+
+    @data(None, "foo")
+    def test_supported_error(self, stream):
+        self.assertRaises(AttributeError,
+                          colorizer.AnsiColorizer.supported, stream)
+
+    @data(("foo", "red", "31"), ("foo", "blue", "34"))
+    @unpack
+    def test_write_string_valid_color(self, text, color, color_code):
+        output = six.StringIO()
+        c = colorizer.AnsiColorizer(output)
+        c.write(text, color)
+        self.assertIn(text, output.getvalue())
+        self.assertIn(color_code, output.getvalue())
+
+    @data(("foo", None), ("foo", "invalid_color"))
+    @unpack
+    def test_write_string_invalid_color(self, text, color):
+        output = six.StringIO()
+        c = colorizer.AnsiColorizer(output)
+        self.assertRaises(KeyError, c.write, text, color)