add unit tests for freqresp/evalfr warnings/errors

murrayrm · bnavigator · commit 1bf445bbc885 · 2021-01-07T10:36:48.000+01:00
diff --git a/control/frdata.py b/control/frdata.py
@@ -421,7 +421,7 @@ def __call__(self, s, squeeze=True):
             frequency values.
         """
         if any(abs(np.array(s, ndmin=1).real) > 0):
-            raise ValueError("__call__: FRD systems can only accept"
+            raise ValueError("__call__: FRD systems can only accept "
                             "purely imaginary frequencies")
         # need to preserve array or scalar status
         if hasattr(s, '__len__'):
diff --git a/control/tests/frd_test.py b/control/tests/frd_test.py
@@ -405,11 +405,15 @@ def test_eval(self):
         np.testing.assert_almost_equal(sys_tf(1j), frd_tf(1j))
 
         # Should get an error if we evaluate at an unknown frequency
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match="not .* in frequency list"):
             frd_tf.eval(2)
 
+        # Should get an error if we evaluate at an complex number
+        with pytest.raises(ValueError, match="can only accept real-valued"):
+            frd_tf.eval(2 + 1j)
+
         # Should get an error if we use __call__ at real-valued frequency
-        with pytest.raises(ValueError):
+        with pytest.raises(ValueError, match="only accept purely imaginary"):
             frd_tf(2)
 
     def test_repr_str(self):
diff --git a/control/tests/statesp_test.py b/control/tests/statesp_test.py
@@ -376,6 +376,12 @@ def test_freq_resp(self):
         np.testing.assert_almost_equal(phase, true_phase)
         np.testing.assert_equal(omega, true_omega)
 
+        # Deprecated version of the call (should return warning)
+        with pytest.warns(DeprecationWarning, match="will be removed"):
+            from control import freqresp
+            mag, phase, omega = sys.freqresp(true_omega)
+            np.testing.assert_almost_equal(mag, true_mag)
+
     def test_is_static_gain(self):
         A0 = np.zeros((2,2))
         A1 = A0.copy()
