keep warnings clean + update impulse() default input to None

murrayrm · murrayrm · commit ad3310952f43 · 2021-01-14T12:01:45.000-08:00
diff --git a/control/tests/timeresp_test.py b/control/tests/timeresp_test.py
@@ -728,6 +728,9 @@ def test_squeeze(self, fcn, nstate, nout, ninp, squeeze, shape):
                         "requires slycot.")
         else:
             sys = fcn(ct.rss(nstate, nout, ninp, strictly_proper=True))
+
+        # Keep track of expect users warnings
+        warntype = UserWarning if sys.inputs > 1 else None
         
         # Compute the length of the frequency array
         tvec = np.linspace(0, 1, 8)
@@ -736,13 +739,15 @@ def test_squeeze(self, fcn, nstate, nout, ninp, squeeze, shape):
             np.reshape(np.sin(tvec), (1, 8)))
 
         # Pass squeeze argument and make sure the shape is correct
-        _, yvec = ct.impulse_response(sys, tvec, squeeze=squeeze)
+        with pytest.warns(warntype, match="Converting MIMO system"):
+            _, yvec = ct.impulse_response(sys, tvec, squeeze=squeeze)
         assert yvec.shape == shape
 
         _, yvec = ct.initial_response(sys, tvec, 1, squeeze=squeeze)
         assert yvec.shape == shape
 
-        _, yvec = ct.step_response(sys, tvec, squeeze=squeeze)
+        with pytest.warns(warntype, match="Converting MIMO system"):
+            _, yvec = ct.step_response(sys, tvec, squeeze=squeeze)
         assert yvec.shape == shape
 
         _, yvec, xvec = ct.forced_response(
@@ -772,13 +777,15 @@ def test_squeeze(self, fcn, nstate, nout, ninp, squeeze, shape):
         ct.config.set_defaults('control', squeeze=False)
         
         # Pass squeeze argument and make sure the shape is correct
-        _, yvec = ct.impulse_response(sys, tvec)
+        with pytest.warns(warntype, match="Converting MIMO system"):
+            _, yvec = ct.impulse_response(sys, tvec)
         assert yvec.shape == (sys.outputs, 8)
 
         _, yvec = ct.initial_response(sys, tvec, 1)
         assert yvec.shape == (sys.outputs, 8)
 
-        _, yvec = ct.step_response(sys, tvec)
+        with pytest.warns(warntype, match="Converting MIMO system"):
+            _, yvec = ct.step_response(sys, tvec)
         assert yvec.shape == (sys.outputs, 8)
 
         _, yvec, xvec = ct.forced_response(
diff --git a/control/timeresp.py b/control/timeresp.py
@@ -737,7 +737,7 @@ def initial_response(sys, T=None, X0=0., input=0, output=None, T_num=None,
     return T, yout
 
 
-def impulse_response(sys, T=None, X0=0., input=0, output=None, T_num=None,
+def impulse_response(sys, T=None, X0=0., input=None, output=None, T_num=None,
                      transpose=False, return_x=False, squeeze=None):
     # pylint: disable=W0622
     """Impulse response of a linear system
