@Test
public void testGetCustomerPhoneNumber() {

    testBusiness.customerPhoneBook.put("Azikiwe, Sarah", sarah.getPhoneNumber());
    testBusiness.customerPhoneBook.put("Adams, Joe", joe.getPhoneNumber());
    testBusiness.customerPhoneBook.put("Hernandez, Alma", alma.getPhoneNumber());
    testBusiness.customerPhoneBook.put("Gustavson, Hannah", hannah.getPhoneNumber());
    String sarahPhone = testBusiness.getCustomerPhoneNumber("Azikiwe, Sarah");
    assertEquals("(208)555-1818", sarahPhone);
    String joePhone = testBusiness.getCustomerPhoneNumber("Adams, Joe");
    assertEquals("(208)888-1900", joePhone);
    String nullPhone = testBusiness.getCustomerPhoneNumber(null);
    assertNull(nullPhone);
    String notCustomer = testBusiness.getCustomerPhoneNumber("Body, No");
    assertNull(notCustomer);
    testBusiness.customerPhoneBook.clear();
}