import org.junit.jupiter.api.Test; import static org.junit.jupiter.api.Assertions.*; class PhoneBookTest { @Test void test() { PhoneBook.add(911, "police"); PhoneBook.add(76213, "Mom"); PhoneBook.add(17239, "Bob"); assertEquals("Mom", PhoneBook.find(76213)); assertEquals("not found", PhoneBook.find(910)); assertEquals("police", PhoneBook.find(911)); PhoneBook.del(910); PhoneBook.del(911); assertEquals("not found", PhoneBook.find(911)); assertEquals("Mom", PhoneBook.find(76213)); PhoneBook.add(76213, "daddy"); assertEquals("daddy", PhoneBook.find(76213)); } }