Business { public String getCustomerPhoneNumber(String lastAndFirstName) { if(lastAndFirstName == null){ return null; } return customerPhoneBook.get(lastAndFirstName); } Business(); void addEmployee(EmployeeBean anEmployee); EmployeeBean getEmployee(String lastAndFirstName); String getCustomerPhoneNumber(String lastAndFirstName); String getAllCustomerPhoneNumbers(); void addCustomerToPhoneBook(CustomerBean aCustomer);  }
@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(); }