dtonhofer

dtonhofer

Functional Programming in Java, Second Edition: Functional Programming in Java, Second Edition: JUnit code improvements for Chapter 11, pages 184 ff “Refactoring More Complex loops”

The same remarks apply as for “Refactoring the Traditional for Loop”

  • No init()
  • Classes under test implement a common interface that is called in tests.
  • Negative tests which apply for input less than 1900, resulting in exceptions.
package chapter11;

import org.junit.jupiter.api.Test;

import java.time.Year;
import java.util.stream.IntStream;

import static org.junit.jupiter.api.Assertions.*;

// Everything is inside the MoreComplexLoopTest class for convenience.
// Documentation for java.time.Year.isLeap()
// https://docs.oracle.com/javase/8/docs/api/java/time/Year.html#isLeap--

public class MoreComplexLoopTest {

    interface LeapYears {

        int countFrom1900(int upTo);

    }

    static class LeapYearCountBefore implements LeapYears {

        public int countFrom1900(int upTo) {
            if (upTo < 1900) {
                throw new IllegalArgumentException("The passed value is < 1900: " + upTo);
            }
            int count = 0;
            for (int year = 1900; year <= upTo; year += 4) {
                if (Year.isLeap(year)) {
                    count++;
                }
            }
            return count;
        }

    }

    static class LeapYearCountAfter implements LeapYears {

        public int countFrom1900(int upTo) {
            if (upTo < 1900) {
                throw new IllegalArgumentException("The passed value is < 1900: " + upTo);
            }
            return (int) IntStream.iterate(1900, year -> year <= upTo, year -> year + 4)
                    .filter(Year::isLeap)
                    .count();
        }

    }

    private static void commonLeapYearsTests(final LeapYears leapYears) {
        assertAll(
                () -> assertEquals(0, leapYears.countFrom1900(1900)),
                () -> assertEquals(25, leapYears.countFrom1900(2000)),
                () -> assertEquals(27, leapYears.countFrom1900(2010)),
                () -> assertEquals(31, leapYears.countFrom1900(2025)),
                () -> assertEquals(49, leapYears.countFrom1900(2100)),
                () -> assertEquals(267, leapYears.countFrom1900(3000)),
                () -> assertThrows(IllegalArgumentException.class, () -> leapYears.countFrom1900(1800))
        );
    }

    @Test
    void leapYearCountBefore() {
        commonLeapYearsTests(new LeapYearCountBefore());
    }

    @Test
    void leapYearCountAfter() {
        commonLeapYearsTests(new LeapYearCountAfter());
    }

}

Where Next?

Popular Pragmatic Bookshelf topics Top

New
belgoros
Following the steps described in Chapter 6 of the book, I’m stuck with running the migration as described on page 84: bundle exec sequel...
New
jesse050717
Title: Web Development with Clojure, Third Edition, pg 116 Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...
New
raul
Hi Travis! Thank you for the cool book! :slight_smile: I made a list of issues and thought I could post them chapter by chapter. I’m rev...
New
rmurray10127
Title: Intuitive Python: docker run… denied error (page 2) Attempted to run the docker command in both CLI and Powershell PS C:\Users\r...
New
brian-m-ops
#book-python-testing-with-pytest-second-edition Hi. Thanks for writing the book. I am just learning so this might just of been an issue ...
New
brunogirin
When running tox for the first time, I got the following error: ERROR: InterpreterNotFound: python3.10 I realised that I was running ...
New
taguniversalmachine
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
New
tkhobbes
After some hassle, I was able to finally run bin/setup, now I have started the rails server but I get this error message right when I vis...
New
SlowburnAZ
Getting an error when installing the dependencies at the start of this chapter: could not compile dependency :exla, "mix compile" failed...
New

Other popular topics Top

Exadra37
I am thinking in building or buy a desktop computer for programing, both professionally and on my free time, and my choice of OS is Linux...
New
DevotionGeo
I know that -t flag is used along with -i flag for getting an interactive shell. But I cannot digest what the man page for docker run com...
New
New
AstonJ
Do the test and post your score :nerd_face: :keyboard: If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
Exadra37
Oh just spent so much time on this to discover now that RancherOS is in end of life but Rancher is refusing to mark the Github repo as su...
New
New
AstonJ
Biggest jackpot ever apparently! :upside_down_face: I don’t (usually) gamble/play the lottery, but working on a program to predict the...
New
New
PragmaticBookshelf
Programming Ruby is the most complete book on Ruby, covering both the language itself and the standard library as well as commonly used t...
New
AstonJ
If you’re getting errors like this: psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory ...
New

Latest in Functional Programming in Java, Second Edition

Functional Programming in Java, Second Edition Portal

Sub Categories: