private void assertOperandReferenceTo(int opIndex, Instruction instr, Address to) {
		Reference[] refs = instr.getOperandReferences(opIndex);
		assertEquals("Operand " + opIndex + " num refs", 1, refs.length);
		assertEquals("Operand " + opIndex + " Ref Check", to, refs[0].getToAddress());
	}
quick and dirty test of the ProgramContextImpl just to see
if the values are being set for specified address range.
The ProgramContextPlugin will be a more complete test
program, with a gui interface to specify the values and
select/highlight an address range.
Ghidra/Features/Base/src/test/java/ghidra/program/util/ConstantPropogationReferenceTest.java