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

jon
Some minor things in the paper edition that says “3 2020” on the title page verso, not mentioned in the book’s errata online: p. 186 But...
New
brianokken
Many tasks_proj/tests directories exist in chapters 2, 3, 5 that have tests that use the custom markers smoke and get, which are not decl...
New
edruder
I thought that there might be interest in using the book with Rails 6.1 and Ruby 2.7.2. I’ll note what I needed to do differently here. ...
New
herminiotorres
Hi @Margaret , On page VII the book tells us the example and snippets will be all using Elixir version 1.11 But on page 3 almost the en...
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
alanq
This isn’t directly about the book contents so maybe not the right forum…but in some of the code apps (e.g. turbo/06) it sends a TURBO_ST...
New
digitalbias
Title: Build a Weather Station with Elixir and Nerves: Problem connecting to Postgres with Grafana on (page 64) If you follow the defau...
New
jwandekoken
Book: Programming Phoenix LiveView, page 142 (157/378), file lib/pento_web/live/product_live/form_component.ex, in the function below: d...
New
Keton
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
New
dachristenson
I just bought this book to learn about Android development, and I’m already running into a major issue in Ch. 1, p. 20: “Update activity...
New

Other popular topics Top

AstonJ
A thread that every forum needs! Simply post a link to a track on YouTube (or SoundCloud or Vimeo amongst others!) on a separate line an...
New
DevotionGeo
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
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
PragmaticBookshelf
Tailwind CSS is an exciting new CSS framework that allows you to design your site by composing simple utility classes to create complex e...
New
foxtrottwist
A few weeks ago I started using Warp a terminal written in rust. Though in it’s current state of development there are a few caveats (tab...
New
New
DevotionGeo
I have always used antique keyboards like Cherry MX 1800 or Cherry MX 8100 and almost always have modified the switches in some way, like...
New
PragmaticBookshelf
Get the comprehensive, insider information you need for Rails 8 with the new edition of this award-winning classic. Sam Ruby @rubys ...
New
mindriot
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
New
PragmaticBookshelf
Use advanced functional programming principles, practical Domain-Driven Design techniques, and production-ready Elixir code to build scal...
New

Latest in Functional Programming in Java, Second Edition

Functional Programming in Java, Second Edition Portal

Sub Categories: