diff --git a/tests/mocks.py b/tests/mocks.py
index f60a9ee..3a5aac3 100644
--- a/tests/mocks.py
+++ b/tests/mocks.py
@@ -4,6 +4,8 @@ import mock
 import shlex
 import subprocess
 
+from bumblebee.output import Widget
+
 class MockPopen(object):
     def __init__(self, module):
         self._patch = mock.patch("{}.subprocess.Popen".format(module))
@@ -24,4 +26,64 @@ class MockPopen(object):
     def cleanup(self):
         self._patch.stop()
 
+class MockInput(object):
+    def __init__(self):
+        self._callbacks = {}
+    def start(self):
+        pass
+
+    def stop(self):
+        pass
+
+    def get_callback(self, uid):
+        return self._callbacks.get(uid, None)
+
+    def register_callback(self, obj, button, cmd):
+        if not obj:
+            return
+        self._callbacks[obj.id] = {
+            "button": button,
+            "command": cmd,
+        }
+
+class MockOutput(object):
+    def start(self):
+        pass
+
+    def stop(self):
+        pass
+
+    def draw(self, widget, engine, module):
+        engine.stop()
+
+    def begin(self):
+        pass
+
+    def flush(self):
+        pass
+
+    def end(self):
+        pass
+
+class MockEngine(object):
+    def __init__(self):
+        self.input = MockInput()
+
+class MockWidget(Widget):
+    def __init__(self, text):
+        super(MockWidget, self).__init__(text)
+        self._text = text
+        self.module = None
+        self.attr_state = ["state-default"]
+        self.id = "none"
+
+    def state(self):
+        return self.attr_state
+
+    def update(self, widgets):
+        pass
+
+    def full_text(self):
+        return self._text
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/tests/test_engine.py b/tests/test_engine.py
new file mode 100644
index 0000000..5623bbf
--- /dev/null
+++ b/tests/test_engine.py
@@ -0,0 +1,83 @@
+# pylint: disable=C0103,C0111,W0703,W0212
+
+import shlex
+import unittest
+
+from bumblebee.error import ModuleLoadError
+from bumblebee.engine import Engine
+from bumblebee.config import Config
+import bumblebee.input
+
+from mocks import MockOutput, MockInput
+
+class TestEngine(unittest.TestCase):
+    def setUp(self):
+        self.engine = Engine(config=Config(), output=MockOutput(), inp=MockInput())
+        self.singleWidgetModule = [{"module": "test", "name": "a"}]
+        self.testModule = "test"
+        self.invalidModule = "no-such-module"
+        self.testModuleSpec = "bumblebee.modules.{}".format(self.testModule)
+        self.testModules = [
+            {"module": "test", "name": "a"},
+            {"module": "test", "name": "b"},
+        ]
+
+    def test_stop(self):
+        self.assertTrue(self.engine.running())
+        self.engine.stop()
+        self.assertFalse(self.engine.running())
+
+    def test_load_module(self):
+        module = self.engine._load_module(self.testModule)
+        self.assertEquals(module.__module__, self.testModuleSpec)
+
+    def test_load_invalid_module(self):
+        with self.assertRaises(ModuleLoadError):
+            self.engine._load_module(self.invalidModule)
+
+    def test_load_none(self):
+        with self.assertRaises(ModuleLoadError):
+            self.engine._load_module(None)
+
+    def test_load_modules(self):
+        modules = self.engine.load_modules(self.testModules)
+        self.assertEquals(len(modules), len(self.testModules))
+        self.assertEquals(
+            [module.__module__ for module in modules],
+            [self.testModuleSpec for module in modules]
+        )
+
+    def test_run(self):
+        self.engine.load_modules(self.singleWidgetModule)
+        try:
+            self.engine.run()
+        except Exception as e:
+            self.fail(e)
+
+    def test_custom_cmd(self):
+        testmodules = [
+            { "name": "test", "button": "test.left-click", "action": "echo" },
+            { "name": "test:alias", "button": "alias.right-click", "action": "echo2" },
+        ]
+        cmd = "-m"
+        for test in testmodules:
+            cmd += " " + test["name"]
+        cmd += " -p"
+        for test in testmodules:
+            cmd += " " + test["button"] + "=" + test["action"]
+        cfg = Config(shlex.split(cmd))
+        inp = MockInput()
+        engine = Engine(config=cfg, output=MockOutput(), inp=inp)
+
+        i = 0
+        for module in engine.modules():
+            callback = inp.get_callback(module.id)
+            self.assertTrue(callback is not None)
+            self.assertEquals(callback["command"], testmodules[i]["action"])
+            if "left" in testmodules[i]["button"]:
+                self.assertTrue(callback["button"], bumblebee.input.LEFT_MOUSE)
+            if "right" in testmodules[i]["button"]:
+                self.assertTrue(callback["button"], bumblebee.input.RIGHT_MOUSE)
+            i += 1
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
diff --git a/tests/test_module.py b/tests/test_module.py
new file mode 100644
index 0000000..6e1c9b2
--- /dev/null
+++ b/tests/test_module.py
@@ -0,0 +1,89 @@
+# pylint: disable=C0103,C0111,W0703
+
+import unittest
+
+from bumblebee.engine import Module
+from bumblebee.config import Config
+from mocks import MockWidget
+
+class TestModule(unittest.TestCase):
+    def setUp(self):
+        self.widgetName = "foo"
+        self.widget = MockWidget(self.widgetName)
+        self.config = Config()
+        self.anyWidgetName = "random-widget-name"
+        self.noSuchModule = "this-module-does-not-exist"
+        self.moduleWithoutWidgets = Module(engine=None, widgets=None)
+        self.moduleWithOneWidget = Module(engine=None, widgets=self.widget, config={"config": self.config})
+        self.moduleWithMultipleWidgets = Module(engine=None,
+            widgets=[self.widget, self.widget, self.widget]
+        )
+
+        self.anyConfigName = "cfg"
+        self.anotherConfigName = "cfg2"
+        self.anyModule = Module(engine=None, widgets=self.widget, config={
+            "name": self.anyConfigName, "config": self.config
+        })
+        self.anotherModule = Module(engine=None, widgets=self.widget, config={
+            "name": self.anotherConfigName, "config": self.config
+        })
+        self.anyKey = "some-parameter"
+        self.anyValue = "value"
+        self.anotherValue = "another-value"
+        self.emptyKey = "i-do-not-exist"
+        self.config.set("{}.{}".format(self.anyConfigName, self.anyKey), self.anyValue)
+        self.config.set("{}.{}".format(self.anotherConfigName, self.anyKey), self.anotherValue)
+
+    def test_empty_widgets(self):
+        self.assertEquals(self.moduleWithoutWidgets.widgets(), [])
+
+    def test_single_widget(self):
+        self.assertEquals(self.moduleWithOneWidget.widgets(), [self.widget])
+
+    def test_multiple_widgets(self):
+        for widget in self.moduleWithMultipleWidgets.widgets():
+            self.assertEquals(widget, self.widget)
+
+    def test_retrieve_widget_by_name(self):
+        widget = MockWidget(self.anyWidgetName)
+        widget.name = self.anyWidgetName
+        module = Module(engine=None, widgets=[self.widget, widget, self.widget])
+        retrievedWidget = module.widget(self.anyWidgetName)
+        self.assertEquals(retrievedWidget, widget)
+
+    def test_retrieve_widget_by_id(self):
+        widget = MockWidget(self.anyWidgetName)
+        widget.id = self.anyWidgetName
+        module = Module(engine=None, widgets=[self.widget, widget, self.widget])
+        retrievedWidget = module.widget_by_id(self.anyWidgetName)
+        self.assertEquals(retrievedWidget, widget)
+
+    def test_retrieve_missing_widget(self):
+        module = self.moduleWithMultipleWidgets
+
+        widget = module.widget(self.noSuchModule)
+        self.assertEquals(widget, None)
+
+        widget = module.widget_by_id(self.noSuchModule)
+        self.assertEquals(widget, None)
+
+    def test_threshold(self):
+        module = self.moduleWithOneWidget
+        module.name = self.widgetName
+
+        self.config.set("{}.critical".format(self.widgetName), 10.0)
+        self.config.set("{}.warning".format(self.widgetName), 8.0)
+        self.assertEquals("critical", module.threshold_state(10.1, 0, 0))
+        self.assertEquals("warning", module.threshold_state(10.0, 0, 0))
+        self.assertEquals(None, module.threshold_state(8.0, 0, 0))
+        self.assertEquals(None, module.threshold_state(7.9, 0, 0))
+
+    def test_parameters(self):
+        self.assertEquals(self.anyModule.parameter(self.anyKey), self.anyValue)
+        self.assertEquals(self.anotherModule.parameter(self.anyKey), self.anotherValue)
+
+    def test_default_parameters(self):
+        self.assertEquals(self.anyModule.parameter(self.emptyKey), None)
+        self.assertEquals(self.anyModule.parameter(self.emptyKey, self.anyValue), self.anyValue)
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4