@Test
	public void testGenerateChildren_ReadReference_CallInstruction_ToData_ExternalReference_NonFunctionSymbol()
			throws Exception {

		//
		// Read reference from an instruction with a flow type that is a call, to a external place
		//

		createCallInstruction();

		builder.createMemoryReference(firstCalledFunctionAddress, "0x1000", RefType.READ,
			SourceType.USER_DEFINED);

		// put a external reference on the data at the 'to' address
		builder.createExternalReference("0x1000", "ExternalLib", "ExternalLabel", 0);

		List<GTreeNode> children = node1.generateChildren(TaskMonitor.DUMMY);
		assertTrue(children.isEmpty());
	}
This test class is covering the various types of 'calls' a function can make, such as a
direct call instruction, or through a user-defined reference.   External calls are also a bit
tricky.   This test was created by following the code paths in {@link OutgoingCallNode}
and making sure that each path was followed.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/plugin/core/calltree/OutgoingCallNodeTest.java