if (this == obj) {
            return true;
        }

        if (obj == null) {
            return false;
        }

        if (!UrlSource.class.equals(obj.getClass())) {
            return false;
        }

        UrlSource other = (UrlSource) obj;
        return Objects.equals(url.toExternalForm(), other.url.toExternalForm());
    }

                NullPointerException.class, () -> new UrlSource(null), "Should fail, since you must specify a url");
        assertEquals("url cannot be null", e.getMessage());
    }

    @Test
    void testGetInputStream() throws Exception {
        URL txtFile = new File("target/test-classes/source.txt").toURI().toURL();
        UrlSource source = new UrlSource(txtFile);
        try (InputStream is = source.getInputStream();