@Test
	public void testRegisterNameLookup() {
		ProgramContext programContext = program.getProgramContext();
		boolean didSomething = false;
		for (String regName : programContext.getRegisterNames()) {
			Register reg = programContext.getRegister(regName);
			assertNotNull(reg);
			assertEquals(regName, reg.getName());
			assertTrue(reg == programContext.getRegister(regName.toLowerCase()));
			assertTrue(reg == programContext.getRegister(regName.toUpperCase()));
			didSomething = true;
		}
		assertTrue(didSomething);
	}
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.slow/java/ghidra/program/util/ProgramContextTest.java