private Map<String, DataTypeNode> getNodes(DataTypeManager dtm) {

		DataTypeArchiveGTree gTree = provider.getGTree();
		GTreeNode rootNode = gTree.getViewRoot();
		GTreeNode dtmNode = rootNode.getChild(dtm.getName());
		assertNotNull(dtmNode);

		expandNode(dtmNode);

		Map<String, DataTypeNode> nodesByName = new HashMap<>();
		Iterator<GTreeNode> it = dtmNode.iterator(true);
		for (GTreeNode node : CollectionUtils.asIterable(it)) {
			if (!(node instanceof DataTypeNode)) {
				continue;
			}
			DataTypeNode dtNode = (DataTypeNode) node;
			DataType dt = dtNode.getDataType();
			nodesByName.put(dt.getName(), dtNode);
		}

		return nodesByName;
	}
Tests for managing categories through the data manager plugin and tests for
actions being enabled when a node is selected.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/plugin/core/datamgr/DataTypeManagerPluginTest.java