add unit test for state space system with no transmission zero

murrayrm · murrayrm · commit 7b04c01fd549 · 2018-07-07T13:26:08.000-07:00
diff --git a/control/tests/statesp_test.py b/control/tests/statesp_test.py
@@ -42,6 +42,11 @@ def testPole(self):
 
         np.testing.assert_array_almost_equal(p, true_p)
 
+    def testEmptyZero(self):
+        """Test to make sure zero() works with no zeros in system"""
+        sys = _convertToStateSpace(TransferFunction([1], [1,2,1]))
+        np.testing.assert_array_equal(sys.zero(), np.array([]))
+
     @unittest.skipIf(not slycot_check(), "slycot not installed")
     def testMIMOZero_nonsquare(self):
         """Evaluate the zeros of a MIMO system."""
