code: @Test public void shouldInvokeImportDetected() throws IOException {
    final AtomicInteger times=new AtomicInteger();
    victim=new CssImportPreProcessor(){
      @Override protected void onImportDetected(    final String foundImportUri){
        times.incrementAndGet();
      }
    }
  ;
    WroTestUtils.initProcessor(victim);
    final Resource resource=Resource.create("someResource.css");
    final Reader reader=new StringReader("@import('/path/to/invalid.css');");
    victim.process(resource,reader,new StringWriter());
    assertEquals(1,times.get());
  }
  