diff --git a/tests/modules/core/test_cpu.py b/tests/modules/core/test_cpu.py
index 9ea85ed..eca2362 100644
--- a/tests/modules/core/test_cpu.py
+++ b/tests/modules/core/test_cpu.py
@@ -1,7 +1,71 @@
 import pytest
+from unittest import TestCase, mock
+
+import core.config
+import core.widget
+import modules.core.cpu
 
 pytest.importorskip("psutil")
 
-def test_load_module():
-    __import__("modules.core.cpu")
+def build_module():
+    config = core.config.Config([])
+    return modules.core.cpu.Module(config=config, theme=None)
+
+def cpu_widget(module):
+    return module.widgets()[0]
+
+class TestCPU(TestCase):
+    def test_load_module(self):
+        __import__("modules.core.cpu")
+
+    @mock.patch('psutil.cpu_percent')
+    def test_cpu_percent(self, cpu_percent_mock):
+        cpu_percent_mock.return_value = 5
+        module = build_module()
+
+        assert cpu_widget(module).full_text() == '5.0%'
+
+    @mock.patch('psutil.cpu_percent')
+    def test_cpu_percent_update(self, cpu_percent_mock):
+        cpu_percent_mock.return_value = 10
+        module = build_module()
+
+        assert cpu_widget(module).full_text() == '10.0%'
+
+        cpu_percent_mock.return_value = 20
+        module.update()
+
+        assert cpu_widget(module).full_text() == '20.0%'
+
+    @mock.patch('psutil.cpu_percent')
+    def test_healthy_state(self, cpu_percent_mock):
+        cpu_percent_mock.return_value = 50
+        module = build_module()
+
+        assert module.state(None) == None
+
+    @mock.patch('psutil.cpu_percent')
+    def test_warning_state(self, cpu_percent_mock):
+        cpu_percent_mock.return_value = 75
+        module = build_module()
+
+        assert module.state(None) == 'warning'
+
+    @mock.patch('psutil.cpu_percent')
+    def test_critical_state(self, cpu_percent_mock):
+        cpu_percent_mock.return_value = 82
+        module = build_module()
+
+        assert module.state(None) == 'critical'
+
+    @mock.patch('core.input.register')
+    def test_register_left_mouse_action(self, input_register_mock):
+        module = build_module()
+
+        input_register_mock.assert_called_with(
+            module,
+            button=core.input.LEFT_MOUSE,
+            cmd='gnome-system-monitor'
+        )
+