### Question:
IllegalURItargetDetector { public boolean isIllegal(URI uri) { if (uri == null) { return true; } String host = uri.getHost(); if (host == null) { return true; } return loopbackfinder.isLoopback(host); }  boolean isIllegal(URI uri);  }### Answer:
@Test public void null_is_always_illegal() { detectorToTest.loopbackfinder=null; assertTrue(detectorToTest.isIllegal(null)); }