private <E extends Exception> void tx(ExceptionalCallback<E> c) {
		int txId = program.startTransaction("Test - Function in Transaction");
		boolean commit = true;
		try {
			c.call();
			program.flushEvents();
		}
		catch (Exception e) {
			commit = false;
			failWithException("Exception modifying program '" + program.getName() + "'", e);
		}
		finally {
			program.endTransaction(txId, commit);
		}
	}
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