import org.junit.jupiter.api.Test;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;

class UrlSourceTest {

    @Test
    void testUrlSource() {
        NullPointerException e = assertThrows(
                NullPointerException.class, () -> new UrlSource(null), "Should fail, since you must specify a url");
        assertEquals("url cannot be null", e.getMessage());