diff --git a/tests/test_util.py b/tests/test_util.py
index 64c320f..07d6d3a 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -1,12 +1,12 @@
 # pylint: disable=C0103,C0111
 
-import mock
 import unittest
 import re
 
 import tests.mocks as mocks
 
-from bumblebee.util import *
+import bumblebee.util as bu
+
 
 class TestUtil(unittest.TestCase):
     def setUp(self):
@@ -18,48 +18,56 @@ class TestUtil(unittest.TestCase):
         self.popen.cleanup()
 
     def test_bytefmt(self):
-        self.assertEquals(bytefmt(10), "10.00B")
-        self.assertEquals(bytefmt(15*1024), "15.00KiB")
-        self.assertEquals(bytefmt(20*1024*1024), "20.00MiB")
-        self.assertEquals(bytefmt(22*1024*1024*1024), "22.00GiB")
-        self.assertEquals(bytefmt(35*1024*1024*1024*1024), "35840.00GiB")
+        self.assertEquals(bu.bytefmt(10), "10.00B")
+        self.assertEquals(bu.bytefmt(15 * 1024), "15.00KiB")
+        self.assertEquals(bu.bytefmt(20 * 1024 * 1024), "20.00MiB")
+        self.assertEquals(bu.bytefmt(22 * 1024 * 1024 * 1024), "22.00GiB")
+        self.assertEquals(bu.bytefmt(35 * 1024 * 1024 * 1024 * 1024), "35840.00GiB")
 
     def test_durationfmt(self):
-        self.assertEquals(durationfmt(00), "00:00")
-        self.assertEquals(durationfmt(25), "00:25")
-        self.assertEquals(durationfmt(60), "01:00")
-        self.assertEquals(durationfmt(119), "01:59")
-        self.assertEquals(durationfmt(3600), "01:00:00")
-        self.assertEquals(durationfmt(7265), "02:01:05")
+        self.assertEquals(bu.durationfmt(00), "00:00")
+        self.assertEquals(bu.durationfmt(25), "00:25")
+        self.assertEquals(bu.durationfmt(60), "01:00")
+        self.assertEquals(bu.durationfmt(119), "01:59")
+        self.assertEquals(bu.durationfmt(3600), "01:00:00")
+        self.assertEquals(bu.durationfmt(7265), "02:01:05")
 
     def test_execute(self):
-        execute(self.some_command_with_args)
+        bu.execute(self.some_command_with_args)
         self.assertTrue(self.popen.mock.popen.called)
         self.popen.mock.popen.assert_call(self.some_command_with_args)
         self.assertTrue(self.popen.mock.communicate.called)
 
     def test_execute_nowait(self):
-        execute(self.some_command_with_args, False)
+        bu.execute(self.some_command_with_args, False)
         self.assertTrue(self.popen.mock.popen.called)
         self.popen.mock.popen.assert_call(self.some_command_with_args)
         self.assertFalse(self.popen.mock.communicate.called)
 
     def test_execute_utf8(self):
-        self.popen.mock.communicate.return_value = [ self.some_utf8, None ]
+        self.popen.mock.communicate.return_value = [self.some_utf8, None]
         self.test_execute()
 
     def test_execute_error(self):
         self.popen.mock.returncode = 1
 
         with self.assertRaises(RuntimeError):
-            execute(self.some_command_with_args)
+            bu.execute(self.some_command_with_args)
 
     def test_which(self):
+        # test for a binary that has to be somewhere
+        print(bu.which("ls"))
+        self.assertTrue(re.search('/(ls)$', bu.which("ls")))
+
+        # test for a binary that is not necessarily there
         program = "iwgetid"
         self.assertTrue(
-            which(program) is None or 
-            re.search('/(' + program + ')$', which(program))
+            bu.which(program) is None or
+            re.search('/(' + program + ')$', bu.which(program))
         )
 
+        # test if which also works with garbage input
+        self.assertTrue(bu.which("qwertygarbage") is None)
+
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4