Assert.assertNull("Filtering on a null object should return null", url_validator.filter(null));
Assert.assertNull("Invalid url: example.com/file[/].html", url_validator.filter("example.com/file[/].html"));
Assert.assertNull("Invalid url: http://www.example.com/space here.html", url_validator.filter("http://www.example.com/space here.html"));
Assert.assertNull("Invalid url: /main.html", url_validator.filter("/main.html"));
Assert.assertNull("Invalid url: www.example.com/main.html", url_validator.filter("www.example.com/main.html"));
Assert.assertNull("Invalid url: ftp:www.example.com/main.html", url_validator.filter("ftp:www.example.com/main.html"));
Assert.assertNull("Inalid url: http://999.000.456.32/nutch/trunk/README.txt",
url_validator.filter("http://999.000.456.32/nutch/trunk/README.txt"));
Assert.assertNull("Invalid url: http://www.example.com/ma|in\\toc.html", url_validator.filter(" http://www.example.com/ma|in\\toc.html"));
Assert.assertNotNull("Valid url: https://issues.apache.org/jira/NUTCH-1127", url_validator.filter("https://issues.apache.org/jira/NUTCH-1127"));