@Test
public void testToString() {

    Account account = new Account(1, "jad", "Jane", "Doe", 1);
    assertEquals("Account [getAccountId()=1, getUsername()=jad, getFirstName()=Jane, getLastName()=Doe]", account.toString());
    Account accountWithNullStrings = new Account(1, null, null, null, 1);
    assertEquals("Account [getAccountId()=1, getUsername()=null, getFirstName()=null, getLastName()=null]", accountWithNullStrings.toString());
}