Add test for variable iis

Author: metab0t

tests/test_iis.py

@@ -23,3 +23,31 @@ def test_constraint_iis(model_interface):
 
     assert con1_iis
     assert con2_iis
+
+
+def test_variable_iis(model_interface):
+    model = model_interface
+
+    if not hasattr(model, "computeIIS"):
+        pytest.skip("Model interface does not support IIS computation")
+
+    x = model.add_variable(lb=0.0, ub=2.0, name="x")
+    y = model.add_variable(lb=0.0, ub=3.0, name="y")
+
+    con1 = model.add_linear_constraint(x + y, poi.Geq, 6.0)
+
+    model.set_objective(x)
+
+    model.computeIIS()
+
+    con1_iis = model.get_constraint_attribute(con1, poi.ConstraintAttribute.IIS)
+    x_lb_iis = model.get_variable_attribute(x, poi.VariableAttribute.IISLowerBound)
+    x_ub_iis = model.get_variable_attribute(x, poi.VariableAttribute.IISUpperBound)
+    y_lb_iis = model.get_variable_attribute(y, poi.VariableAttribute.IISLowerBound)
+    y_ub_iis = model.get_variable_attribute(y, poi.VariableAttribute.IISUpperBound)
+
+    assert con1_iis
+    assert not x_lb_iis
+    assert x_ub_iis
+    assert not y_lb_iis
+    assert y_ub_iis