diff --git a/tests/mocks.py b/tests/mocks.py
index ee190f6..4d7eab9 100644
--- a/tests/mocks.py
+++ b/tests/mocks.py
@@ -12,6 +12,22 @@ import random
 def rand(cnt):
     return "".join(random.choice("abcdefghijklmnopqrstuvwxyz0123456789") for i in range(cnt))
 
+def epoll_mock(module=""):
+    if len(module) > 0: module = "{}.".format(module)
+
+    stdin = mock.patch("{}sys.stdin".format(module))
+    select = mock.patch("{}select".format(module))
+    epoll = mock.Mock()
+
+    stdin_mock = stdin.start()
+    select_mock = select.start()
+
+    stdin_mock.fileno.return_value = 1
+    select_mock.epoll.return_value = epoll
+    epoll.poll.return_value = [(stdin_mock.fileno.return_value, 100)]
+
+    return stdin, select, stdin_mock, select_mock
+
 def mouseEvent(stdin, button, inp, module=None, instance=None):
     stdin.readline.return_value = json.dumps({
         "name": module.id if module else rand(10),
diff --git a/tests/modules/test_brightness.py b/tests/modules/test_brightness.py
new file mode 100644
index 0000000..5112e41
--- /dev/null
+++ b/tests/modules/test_brightness.py
@@ -0,0 +1,69 @@
+# pylint: disable=C0103,C0111
+
+import mock
+import unittest
+
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import StringIO
+
+import tests.mocks as mocks
+
+import bumblebee.input
+from bumblebee.config import Config
+from bumblebee.engine import Engine
+from bumblebee.input import I3BarInput, WHEEL_UP, WHEEL_DOWN
+from bumblebee.modules.brightness import Module
+
+class TestBrightnessModule(unittest.TestCase):
+    def setUp(self):
+        self._stdout = mock.patch("sys.stdout", new_callable=StringIO)
+        self.stdout = self._stdout.start()
+
+        self._stdin, self._select, self.stdin, self.select = mocks.epoll_mock("bumblebee.input")
+
+        self.popen = mocks.MockPopen()
+
+        self.config = Config()
+        self.input = I3BarInput()
+        self.engine = mock.Mock()
+        self.engine.input = self.input
+        self.input.need_event = True
+
+        self.module = Module(engine=self.engine, config={ "config": self.config })
+        for widget in self.module.widgets():
+            widget.link_module(self.module)
+            self.anyWidget = widget
+
+    def tearDown(self):
+        self._stdout.stop()
+        self._stdin.stop()
+        self._select.stop()
+        self.popen.cleanup()
+
+    def test_format(self):
+        for widget in self.module.widgets():
+            self.assertEquals(len(widget.full_text()), len("100%"))
+
+    def test_wheel_up(self):
+        mocks.mouseEvent(stdin=self.stdin, button=WHEEL_UP, inp=self.input, module=self.module)
+        self.popen.assert_call("xbacklight +2%")
+
+    def test_wheel_down(self):
+        mocks.mouseEvent(stdin=self.stdin, button=WHEEL_DOWN, inp=self.input, module=self.module)
+        self.popen.assert_call("xbacklight -2%")
+
+    def test_custom_step(self):
+        self.config.set("brightness.step", "10")
+        module = Module(engine=self.engine, config={"config": self.config})
+        mocks.mouseEvent(stdin=self.stdin, button=WHEEL_DOWN, inp=self.input, module=module)
+        self.popen.assert_call("xbacklight -10%")
+
+    def test_update(self):
+        self.popen.mock.communicate.return_value = ("20.0", None)
+        self.module.update_all()
+        self.assertEquals(self.module.brightness(self.anyWidget), "020%")
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4