@Test
public void onHttpClientUpgradeWithoutHandlerAdded() throws Exception {

    handler = new Http2ConnectionHandlerBuilder().frameListener(new Http2FrameAdapter()).server(false).build();
    try {
        handler.onHttpClientUpgrade();
        fail();
    } catch (Http2Exception e) {
        assertEquals(Http2Error.INTERNAL_ERROR, e.error());
    }
}