@Test
	public void testDiffFilter() throws Exception {
		programMerge = new ProgramMergeManager(p1, p2);
		// Check that default filter has all difference types set.
		assertEquals(new ProgramDiffFilter(ProgramDiffFilter.ALL_DIFFS),
			programMerge.getDiffFilter());

		// See if we set it to no differences, that is what we get.
		programMerge.setDiffFilter(new ProgramDiffFilter());
		assertEquals(new ProgramDiffFilter(), programMerge.getDiffFilter());

		// See if we set it to specific differences, that is what we get.
		programMerge.setDiffFilter(new ProgramDiffFilter(
			ProgramDiffFilter.CODE_UNIT_DIFFS | ProgramDiffFilter.COMMENT_DIFFS));
		assertEquals(
			new ProgramDiffFilter(
				ProgramDiffFilter.CODE_UNIT_DIFFS | ProgramDiffFilter.COMMENT_DIFFS),
			programMerge.getDiffFilter());
	}
Test that programMergeFilter works as expected.
Ghidra/Features/Base/src/test.slow/java/ghidra/program/util/ProgramMerge1Test.java