framework_py: Add test of using AbstractValue's in input ports (follo…

…wing up from pybind unique_ptr snafu)

bindings/pydrake/systems/framework_py.cc

@@ -281,6 +281,13 @@ PYBIND11_MODULE(framework, m) {
         [](const System<T>* self, const Context<T>& arg1, int arg2) {
           return self->EvalVectorInput(arg1, arg2);
         }, py_reference_internal)
+    .def(
+        "EvalAbstractInput",
+        [](const System<T>* self, const Context<T>& arg1, int arg2) {
+          return self->EvalAbstractInput(arg1, arg2);
+        }, py_reference,
+        // Keep alive, ownership: `return` keeps `Context` alive.
+        py::keep_alive<0, 2>())
     .def("CalcOutput", &System<T>::CalcOutput)
     // Sugar.
     .def(
@@ -349,9 +356,16 @@ PYBIND11_MODULE(framework, m) {
     .def("get_num_input_ports", &Context<T>::get_num_input_ports)
     .def("FixInputPort",
          py::overload_cast<int, unique_ptr<BasicVector<T>>>(
-             &Context<T>::FixInputPort), py_reference_internal,
+             &Context<T>::FixInputPort),
+         py_reference_internal,
          // Keep alive, ownership: `BasicVector` keeps `self` alive.
          py::keep_alive<3, 1>())
+    .def("FixInputPort",
+         py::overload_cast<int, unique_ptr<AbstractValue>>(
+             &Context<T>::FixInputPort),
+         py_reference_internal,
+         // Keep alive, ownership: `AbstractValue` keeps `self` alive.
+         py::keep_alive<3, 1>())
     .def("get_time", &Context<T>::get_time)
     .def("Clone", &Context<T>::Clone)
     .def("__copy__", &Context<T>::Clone)
@@ -432,8 +446,12 @@ PYBIND11_MODULE(framework, m) {
 
   py::class_<OutputPort<T>>(m, "OutputPort");
 
-  py::class_<SystemOutput<T>>(m, "SystemOutput")
+  py::class_<SystemOutput<T>> system_output(m, "SystemOutput");
+  DefClone(&system_output);
+  system_output
     .def("get_num_ports", &SystemOutput<T>::get_num_ports)
+    .def("get_data", &SystemOutput<T>::get_data,
+         py_reference_internal)
     .def("get_vector_data", &SystemOutput<T>::get_vector_data,
          py_reference_internal);
 

bindings/pydrake/systems/primitives_py.cc

@@ -6,6 +6,7 @@
 #include "drake/systems/primitives/constant_value_source.h"
 #include "drake/systems/primitives/constant_vector_source.h"
 #include "drake/systems/primitives/integrator.h"
+#include "drake/systems/primitives/pass_through.h"
 #include "drake/systems/primitives/signal_logger.h"
 #include "drake/systems/primitives/zero_order_hold.h"
 
@@ -31,6 +32,10 @@ PYBIND11_MODULE(primitives, m) {
   py::class_<Integrator<T>, LeafSystem<T>>(m, "Integrator")
     .def(py::init<int>());
 
+  py::class_<PassThrough<T>, LeafSystem<T>>(m, "PassThrough")
+    .def(py::init<int>())
+    .def(py::init<const AbstractValue&>());
+
   py::class_<ZeroOrderHold<T>, LeafSystem<T>>(m, "ZeroOrderHold")
     .def(py::init<double, int>());
 

bindings/pydrake/systems/test/general_test.py

@@ -12,6 +12,7 @@
     Simulator,
     )
 from pydrake.systems.framework import (
+    AbstractValue,
     BasicVector,
     Diagram,
     DiagramBuilder,
@@ -20,6 +21,7 @@
     Adder,
     ConstantVectorSource,
     Integrator,
+    PassThrough,
     SignalLogger,
     )
 
@@ -165,6 +167,19 @@ def test_signal_logger(self):
         self.assertTrue(t.shape[0] == x.shape[1])
         self.assertAlmostEqual(x[0, -1], t[-1]*kValue, places=2)
 
+    def test_abstract_pass_through(self):
+        model_value = AbstractValue.Make("Hello world")
+        input_value = model_value.Clone()
+        system = PassThrough(model_value)
+        context = system.CreateDefaultContext()
+        context.FixInputPort(0, input_value)
+        output = system.AllocateOutput(context)
+        input_eval = system.EvalAbstractInput(context, 0)
+        self.assertEquals(input_eval.get_value(), input_value.get_value())
+        system.CalcOutput(context, output)
+        output_value = output.get_data(0)
+        self.assertEquals(output_value.get_value(), input_value.get_value())
+
 
 if __name__ == '__main__':
     unittest.main()