Implement MDagModifier::createNode bindings

src/MDagModifier.inl

@@ -1,10 +1,34 @@
-py::class_<MDagModifier>(m, "DagModifier")
+py::class_<MDagModifier>(m, "DagModifier", "DGModifier")
     .def(py::init<>())
 
-    .def("createNode", [](MDagModifier & self, MString type, MObject parent = MObject::kNullObj) -> MObject {
-        throw std::logic_error{"Function not yet implemented."};
-    }, 
-R"pbdoc(Adds an operation to the modifier to create a DAG node of the specified type. 
+    .def("createNode", [](MDagModifier & self, std::string type, MObject parent = MObject::kNullObj) -> MObject {
+        if (!parent.isNull())
+        {
+            validate::has_fn(
+                parent, MFn::kDagNode, 
+                "Cannot createNode - 'parent' must be a 'kDagNode' object , not a '^1s' object."
+            );
+        }
+
+        MString type_name(type.c_str());
+        MStatus status;
+        MObject result = self.createNode(type_name, parent, &status);
+
+        if (status == MS::kInvalidParameter)
+        {
+            MString error_msg("Cannot create dependency node '^1s' - use DGModifier instead.");
+                    error_msg.format(error_msg, type_name);
+            throw pybind11::type_error(error_msg.asChar());
+        } else if (result.isNull()) {
+            MString error_msg("Cannot create unknown node type '^1s'.");
+                    error_msg.format(error_msg, type_name);
+            throw pybind11::type_error(error_msg.asChar());
+        }
+
+        CHECK_STATUS(status)
+
+        return result;
+    }, R"pbdoc(Adds an operation to the modifier to create a DAG node of the specified type. 
 If a parent DAG node is provided the new node will be parented under it. 
 If no parent is provided and the new DAG node is a transform type then it will be parented under the world. 
 In both of these cases, the method returns the new DAG node.
@@ -17,8 +41,27 @@ and it is the transform node which will be returned by the method, not the child
 None of the newly created nodes will be added to the DAG until the modifier's doIt() method is called.)pbdoc")
 
     .def("createNode", [](MDagModifier & self, MTypeId typeId, MObject parent = MObject::kNullObj) -> MObject {
-        throw std::logic_error{"Function not yet implemented."};
-    }, R"pbdoc(Adds an operation to the modifier to create a DAG node of the specified type. 
+        MString type_id_str = MString() + typeId.id();
+
+        MStatus status;
+        MObject result = self.createNode(typeId, parent, &status);
+
+        if (status == MS::kInvalidParameter)
+        {
+            MString error_msg("Cannot create dependency node with type ID '^1s'' - use DGModifier instead.");
+                    error_msg.format(error_msg, type_id_str);
+            throw pybind11::type_error(error_msg.asChar());
+        } else if (result.isNull()) {
+            MString error_msg("Cannot create unknown node with type ID '^1s'.");
+                    error_msg.format(error_msg, type_id_str);
+            throw pybind11::type_error(error_msg.asChar());
+        }
+
+        CHECK_STATUS(status)
+
+        return result;
+    }, 
+R"pbdoc(Adds an operation to the modifier to create a DAG node of the specified type. 
     
 If a parent DAG node is provided the new node will be parented under it. 
 If no parent is provided and the new DAG node is a transform type then it will be parented under the world. 
@@ -33,7 +76,8 @@ None of the newly created nodes will be added to the DAG until the modifier's do
 
     .def("reparentNode", [](MDagModifier & self, MObject node, MObject newParent = MObject::kNullObj) {
         throw std::logic_error{"Function not yet implemented."};
-    }, R"pbdoc(Adds an operation to the modifier to reparent a DAG node under a specified parent.
+    }, 
+R"pbdoc(Adds an operation to the modifier to reparent a DAG node under a specified parent.
 
 If no parent is provided then the DAG node will be reparented under the world, so long as it is a transform type. 
 If it is not a transform type then the doIt() will raise a RuntimeError.)pbdoc");

tests/test_MDagModifier.py

@@ -0,0 +1,62 @@
+import cmdc
+import nose
+
+from nose.plugins.skip import SkipTest
+
+from maya import cmds
+from maya.api import OpenMaya
+
+from . import assert_equals, as_obj, as_plug, new_scene
+
+def test_createNode():
+    raise SkipTest("Cannot test DAGModifier.createNode - not sure how to subclass from DGModifier.")
+
+
+    node = as_obj(cmds.createNode('transform'))
+    type_id = cmdc.FnDependencyNode(node).typeId()
+
+    for name, value in (
+        ['typeName', 'transform'],
+        ['typeId',  cmdc.TypeId(type_id)]
+    ):
+        test_createNode.__doc__ = """Test MDagModifier::createNode if called with a valid {}.""".format(name)
+
+        yield _createNode_pass, value
+
+    for name, value in (
+        ['typeName', 'foobar'],
+        ['typeName', 'network'],
+        ['typeId', cmdc.TypeId(0xdeadbeef)]
+    ):
+        test_createNode.__doc__ = """Test MDagGModifier::createNode raises error if called with an invalid {}.""".format(name)
+
+        yield _createNode_fail, value
+
+
+@nose.with_setup(teardown=new_scene)
+def _createNode_fail(arg):
+    old_nodes = cmds.ls(long=True)
+
+    nose.tools.assert_raises(
+        TypeError, _createNode_pass, arg
+    )
+
+    new_nodes = cmds.ls(long=True)
+
+    assert len(old_nodes) == len(new_nodes), "DagModifier.createNode modified the scene graph."
+
+
+@nose.with_setup(teardown=new_scene)
+def _createNode_pass(arg):
+    old_nodes = cmds.ls(long=True)
+
+    mod = cmdc.DagModifier()
+    node = mod.createNode(arg, cmdc.Object())
+    mod.doIt()
+
+    new_nodes = cmds.ls(long=True)
+
+    add_nodes = set(new_nodes) - set(old_nodes)
+
+    assert not node.isNull(), "Created node is not valid."
+    assert len(add_nodes) == 1, "`ls` did not return new node."