[modules/cpu] Add configurable warning and critical thresholds

The cpu module now has cpu.warning and cpu.critical thresholds. If the
CPU utilization is higher than any of those values, the widget's state
changes to warning or critical, respectively.

see #23

tests/modules/test_cpu.py

@@ -7,14 +7,17 @@ import mock
 import bumblebee.input
 from bumblebee.input import I3BarInput
 from bumblebee.modules.cpu import Module
-from tests.util import MockEngine, assertPopen
+from tests.util import MockEngine, MockConfig, assertPopen
 
 class TestCPUModule(unittest.TestCase):
     def setUp(self):
         self.engine = MockEngine()
         self.engine.input = I3BarInput()
         self.engine.input.need_event = True
-        self.module = Module(engine=self.engine, config={})
+        self.config = MockConfig()
+        self.module = Module(engine=self.engine, config={ "config": self.config })
+        for widget in self.module.widgets():
+            widget.link_module(self.module)
 
     @mock.patch("sys.stdout")
     def test_format(self, mock_output):
@@ -34,4 +37,20 @@ class TestCPUModule(unittest.TestCase):
         mock_input.readline.assert_any_call()
         assertPopen(mock_output, "gnome-system-monitor")
 
+    @mock.patch("psutil.cpu_percent")
+    def test_warning(self, mock_psutil):
+        self.config.set("cpu.critical", "20")
+        self.config.set("cpu.warning", "18")
+        mock_psutil.return_value = 19.0
+        self.module.update(self.module.widgets())
+        self.assertEquals(self.module.widgets()[0].state(), "warning")
+
+    @mock.patch("psutil.cpu_percent")
+    def test_critical(self, mock_psutil):
+        self.config.set("cpu.critical", "20")
+        self.config.set("cpu.warning", "19")
+        mock_psutil.return_value = 21.0
+        self.module.update(self.module.widgets())
+        self.assertEquals(self.module.widgets()[0].state(), "critical")
+
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