Nodes

create_temp_node

The create_temp_node() fixture can be used to create temporary testing nodes and not have to worry about destroying them after the test is over. Additionally, it can be called multiple times to create many temporary nodes.

It supports a limited number of parameters to affect the node creation:

def _create(
    parent: hou.Node,
    node_type_name: str,
    node_name: str | None = None,
    *, run_init_scripts: bool = True
) -> hou.Node:
    """Function to create a test node that will be destroyed on cleanup.

    Args:
        parent: The parent to create the test node under.
        node_type_name: The node type to create.
        node_name: Optional node name.
        run_init_scripts: Whether to run the node initialization scripts.

    Return:
        The created test node.
    """

In the following example we create some temp nodes to test with.

def test_some_func(create_temp_node):
    node1 = create_temp_node(hou.node("/obj"), "geo", "TEST_NODE1", run_init_scripts=False)
    node2 = create_temp_node(hou.node("/obj"), "null", "TEST_NODE2")

    ... # do testing

After the test function is executed, the created nodes will both be destroyed. If the test code itself destroys a node, the hou.ObjectWasDeleted exception will be suppressed.

Existing Test Node Fixtures

There are a number of convenience functions which can be used to automatically find test related nodes in the current hip file based on the test name data.

The underlying tooling will inspect the pytest.FixtureRequest object and construct a number of acceptable node names/paths for the specific test and try to return one of those. If a matching node cannot be found a NoTestNodeError is raised and the test will fail.

The node search order is as follows:

Node matching the exact test name
Node matching the class name + test name (minus “test_” prefix for function name)
Node matching the class name / test name (minus “test_” prefix for function name)
Node matching the class name

In the case of using the test class name, the class name component of the node name can match exactly or be lower case.

For example, a simple test function named test_myfunc would attempt to find a node named test_myfunc under the desired parent node. In the example below this would be an Object node under “/obj”.

def test_myfunc(obj_test_node):
    assert obj_test_node.path() == "/obj/test_myfunc"

For the following test class it is a bit more complicated:

class TestMyFunc:

    def test_none_args(self, obj_test_node):
        pass

Again, we’ll be using an Object node as the example. So, what could a valid obj_test_node path be? From above, the possible nodes found (and their order of precedence) is as follows:

/obj/TestMyFunc_none_args

/obj/testmyfunc_none_args

/obj/TestMyFunc/none_args

/obj/testmyfunc/none_args

/obj/TestMyFunc

/obj/testmyfunc

In the event that no valid nodes could be provided, the raised NoTestNodeError will contain a list of all paths which were tried:

NoTestNodeError: Could not find any matching test nodes: /obj/test_none_args, /obj/TestMyFunc_none_args, /obj/testmyfunc_none_args, /obj/TestMyFunc/none_args, /obj/testmyfunc/none_args, /obj/TestMyFunc, /obj/testmyfunc

Basic Context Fixtures

*_test_node

The *_test_node fixtures will attempt to find a test node under their specific contexts (as detailed above for obj_test_node)

The following contexts are currently provided:

/obj (obj_test_node)
/out (out_test_node)

Object Specific Fixtures

obj_test_geo

The obj_test_geo() fixture will attempt to return the geometry of the display node of the found Object test node.

If the found test node (using obj_test_node()) does not contain SOP nodes a TestNodeDoesNotContainSOPsError is raised.

The returned hou.Geometry object is read only.

def test_get_geo(obj_test_geo, obj_test_node):
    assert obj_test_geo.sopNode() == obj_test_node.displayNode()
    assert obj_test_geo.isReadOnly()

obj_test_geo_copy

The obj_test_geo_copy() fixture is the same as obj_test_geo() however the found geometry is copied/merged into a new hou.Geometry instance and is not read only.

def test_get_geo(obj_test_geo_copy):
    # There is no referenced SOP due to being a standalone hou.Geometry.
    assert obj_test_geo_copy.sopNode() is None
    assert not obj_test_geo_copy.isReadOnly()