@Test
public void testEmptySubset() throws IOException
{

    File testFile = null;
    try
    {
        testFile = new File(
            getClass().getResource("/fontbox/ttf/LiberationSans-Regular.ttf").toURI());
    }
    catch (URISyntaxException e)
    {
        e.printStackTrace();
        fail();
    }
    TrueTypeFont x = new TTFParser().parse(testFile);
    TTFSubsetter ttfSubsetter = new TTFSubsetter(x);
    try
    {
        ttfSubsetter.writeToStream(new ByteArrayOutputStream());
        fail("IllegalStateException should be thrown");
    }
    catch (IllegalStateException e)
    {
        // ok
    }
}