@Test
	public void testAddDiffExternalLabelKeepBoth() throws Exception {
		final String libname = "user32.dll";
		final String parentNamespace = "MyNamespace";
		final String label = "apples";
		final String address1 = "0x100";
		final String address2 = "0x120";

		mtf.initialize("NotepadMergeListingTest", new MergeProgramModifier() {

			@Override
			public void initializeProgram(MergeProgram program) throws Exception {
				program.addMemory("memory", "0x0", 0x200);
			}

			@Override
			public void modifyLatest(MergeProgram mergeProgram) throws Exception {
				Library library =
					mergeProgram.createExternalLibrary(libname, SourceType.USER_DEFINED);
				Namespace namespace =
					mergeProgram.createNamespace(library, parentNamespace, SourceType.USER_DEFINED);
				mergeProgram.addExternalLocation(namespace, label, address1,
					SourceType.USER_DEFINED);

			}

			@Override
			public void modifyPrivate(MergeProgram mergeProgram) throws Exception {
				Library library =
					mergeProgram.createExternalLibrary(libname, SourceType.USER_DEFINED);
				Namespace namespace =
					mergeProgram.createNamespace(library, parentNamespace, SourceType.USER_DEFINED);
				mergeProgram.addExternalLocation(namespace, label, address2,
					SourceType.USER_DEFINED);
			}
		});

		executeMerge(ASK_USER);
		chooseButtonAndApply("Resolve External Add Conflict", KEEP_BOTH_BUTTON);
		waitForMergeCompletion();

		Namespace externalLibrary =
			(Namespace) resultProgram.getSymbolTable().getLibrarySymbol(libname).getObject();
		assertNotNull(externalLibrary);
		Namespace myNamespace =
			resultProgram.getSymbolTable().getNamespace(parentNamespace, externalLibrary);
		assertNotNull(myNamespace);
		SymbolTable symtab = resultProgram.getSymbolTable();

		List<Symbol> symbols = symtab.getSymbols(label, myNamespace);
		assertEquals(2, symbols.size());
		assertTrue(!symbols.get(0).getAddress().equals(symbols.get(1).getAddress()));

	}
The external function merger only detects and merges source differences when a name
difference is being merged.
Ghidra/Features/Base/src/test.slow/java/ghidra/app/merge/listing/ExternalMergerAddTest.java