Parameterize unit tests. Catch edge case of A=0.

Mark-Yeatman · Mark-Yeatman · commit bb16be01ff70 · 2022-06-14T11:26:30.000-04:00
diff --git a/control/passivity.py b/control/passivity.py
@@ -44,6 +44,9 @@ def ispassive(sys):
     [n, m] = D.shape
     D = D + np.nextafter(0, 1)*np.eye(n, m)
 
+    [n, _] = A.shape
+    A = A - np.nextafter(0, 1)*np.eye(n)
+
     def make_LMI_matrix(P):
         V = np.vstack((
             np.hstack((A.T @ P + P@A, P@B)),
@@ -75,7 +78,7 @@ def make_LMI_matrix(P):
     # crunch feasibility solution
     cvx.solvers.options['show_progress'] = False
     sol = cvx.solvers.sdp(c,
-                          Gs=[cvx.matrix(coefficents)],
-                          hs=[cvx.matrix(constants)])
+                        Gs=[cvx.matrix(coefficents)],
+                        hs=[cvx.matrix(constants)])
 
     return (sol["x"] is not None)
diff --git a/control/tests/passivity_test.py b/control/tests/passivity_test.py
@@ -2,7 +2,7 @@
 Author: Mark Yeatman  
 Date: May 30, 2022
 '''
-
+import pytest
 import numpy
 from control import ss, passivity
 from control.tests.conftest import cvxoptonly
@@ -25,39 +25,26 @@ def test_ispassive():
 
     assert(not passivity.ispassive(sys))
 
-
+A_d = numpy.array([[-2, 0], [0, 0]])
+A = numpy.array([[-3, 0], [0, -2]])
+B = numpy.array([[0], [1]])
+C = numpy.array([[-1, 2]])
+D = numpy.array([[1.5]])
 @cvxoptonly
-def test_ispassive_edge_cases():
-    A = numpy.array([[0, 1], [-2, -2]])
-    B = numpy.array([[0], [1]])
-    C = numpy.array([[-1, 2]])
-    D = numpy.array([[1.5]])
-
-    D *= 0
+@pytest.mark.parametrize(
+    "test_input,expected", 
+    [((A,B,C,D*0.0), True), 
+     ((A_d,B,C,D), True), 
+     ((A*1e12,B,C,D*0), True), 
+     ((A,B*0,C*0,D), True),
+     ((A*0,B,C,D), True),
+     ((A*0,B*0,C*0,D*0), True)])
+def test_ispassive_edge_cases(test_input, expected):
 
     # strictly proper
+    A = test_input[0]
+    B = test_input[1]
+    C = test_input[2]
+    D = test_input[3]
     sys = ss(A, B, C, D)
-    assert(passivity.ispassive(sys))
-
-    # ill conditioned
-    A = A*1e12
-    sys = ss(A, B, C, D)
-    assert(passivity.ispassive(sys))
-
-    # different combinations of zero A,B,C,D are 0
-    B *= 0
-    C *= 0
-    assert(passivity.ispassive(sys))
-
-    A *= 0
-    B = numpy.array([[0], [1]])
-    C = numpy.array([[-1, 2]])
-    D = numpy.array([[1.5]])
-    assert(passivity.ispassive(sys))
-
-    B *= 0
-    C *= 0
-    assert(passivity.ispassive(sys))
-
-    A *= 0
-    assert(passivity.ispassive(sys))
+    assert(passivity.ispassive(sys)==expected)
