@Test
	public void testBytesPerLinesChange() throws Exception {

		ByteViewerOptionsDialog d = launchByteViewerOptions();
		FixedBitSizeValueField field =
			(FixedBitSizeValueField) getInstanceField("bytesPerLineField", d);
		runSwing(() -> field.setValue(BigInteger.valueOf(10)));
		pressButtonByText(d.getComponent(), "OK");

		waitForSwing();

		// verify that the bytes per line is 10
		assertEquals(10, plugin.getProvider().getBytesPerLine());
		ByteViewerComponent c = panel.getCurrentComponent();
		assertEquals(10, c.getNumberOfFields());
		assertEquals(8, plugin.getProvider().getOffset());
	}
Basic tests for the byte view plugin
Ghidra/Features/ByteViewer/src/test.slow/java/ghidra/app/plugin/core/byteviewer/ByteViewerPlugin1Test.java