diff --git a/TF_Implementation/test/test_aPID_tf.py b/TF_Implementation/test/test_aPID_tf.py
index 6eba41a..18a7cb4 100644
--- a/TF_Implementation/test/test_aPID_tf.py
+++ b/TF_Implementation/test/test_aPID_tf.py
@@ -14,6 +14,9 @@ class TestAdaptivePIDTf(unittest.TestCase):
         self.input_dim = 3
         self.rbf_model = RBFAdaptiveModel(self.n_centers, self.input_dim)
         self.apid = AdaptivePIDTf(self.Kp, self.Ki, self.Kd, self.rbf_model)
+        self.target = 10.0
+        self.measured_value = 8.0
+        self.dt = 0.1
 
     def test_initialization(self):
         """ Test initialization of the controller."""
@@ -26,6 +29,18 @@ class TestAdaptivePIDTf(unittest.TestCase):
         self.assertEqual(self.apid.integral, 0)
         self.assertEqual(self.apid.derivative, 0)
 
+    def test_update(self):
+        """ Test the update method."""
+        control_signal = self.apid.update(self.target, self.measured_value, self.dt)
+
+        self.assertIsInstance(control_signal, float)
+        self.assertEqual(self.apid.prev_err, self.apid.error)
+
+        integral = self.apid.integral
+        self.assertAlmostEqual(integral, (self.target - self.measured_value) * self.dt)
+
+        derivative = self.apid.derivative
+        self.assertAlmostEqual(derivative, (self.target - self.measured_value)/self.dt)
 
 
 if __name__ == '__main__':