theboreddev

public class RomanNumerals {

    public static String convert(int number) {
        if (number == 5) {
            return "V";
        }
        return "I";
    }
}

theboreddev

    @Test
    public void convert_shouldReturnV() {

        final String romanNumeral = RomanNumerals.convert(5);

        assertThat(romanNumeral, is("V"));
    }

theboreddev

public class RomanNumerals {

    public static String convert(int number) {
        return "";
    }
}

theboreddev

    @Test
    public void convert_shouldReturnI() {

        final String romanNumeral = RomanNumerals.convert(1);

        assertThat(romanNumeral, is("I"));
    }

theboreddev

    @Test
    public void convert_shouldReturnI() {

        final String romanNumeral = RomanNumerals.convert(1);

        assertThat(romanNumeral, is("I"));
    }

theboreddev

        final Customer customer = Customer.builderOf("John", "Smith")
                .withAge(30)
                .build();

        System.out.println(customer.getAddress().orElse("No address present"));

theboreddev

import java.util.Optional;

public class Customer {
    private final String firstName;
    private final String surname;
    private final Integer age;
    private final String address;
    private final String phoneNumber;
    private final Sex sex;

theboreddev

        final Customer testCustomer = new Customer(
                "John",
                "Smith",
                Optional.of(30),
                Optional.of("Flat 0, Some Street, W1 XYZ"),
                Optional.of("01234 567890"),
                Optional.of(Sex.MALE)
        );

theboreddev

        final Customer customer = new Customer(
                "John",
                "Smith",
                Optional.empty(),
                Optional.empty(),
                Optional.empty(),
                Optional.empty()
        );

theboreddev

    static class Customer {
        private final String firstName;
        private final String surname;
        private final Optional<Integer> age;
        private final Optional<String> address;
        private final Optional<String> phoneNumber;
        private final Optional<Sex> sex;


        public Customer(String firstName, String surname, Optional<Integer> age, Optional<String> address, Optional<String> phoneNumber, Optional<Sex> sex) {