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());
}
}
Popular Pragmatic Bookshelf topics
page 20: … protoc command…
I had to additionally run the following go get commands in order to be able to compile protobuf code using go...
New
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
When I try the command to create a pair of migration files I get an error.
user=> (create-migration "guestbook")
Execution error (Ill...
New
Title: Hands-On Rust (Chapter 11: prefab)
Just played a couple of amulet-less games. With a bit of debugging, I believe that your can_p...
New
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
The generated iex result below should list products instead of product for the metadata. (page 67)
iex> product = %Product{}
%Pento....
New
Title: Web Development with Clojure, Third Edition, vB17.0 (p9)
The create table guestbook syntax suggested doesn’t seem to be accepted ...
New
Dear Sophie.
I tried to do the “Authorization” exercise and have two questions:
When trying to plug in an email-service, I found the ...
New
On page 78 the following code appears:
<%= link_to ‘Destroy’, product,
class: ‘hover:underline’,
method: :delete,
data: { confirm...
New
Title: Agile Web Development with Rails 7: (page 70)
I am running windows 11 pro with rails 7.0.3 and ruby 3.1.2p20 (2022-04-12 revision...
New
Other popular topics
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
We have a thread about the keyboards we have, but what about nice keyboards we come across that we want? If you have seen any that look n...
New
Thanks to @foxtrottwist’s and @Tomas’s posts in this thread: Poll: Which code editor do you use? I bought Onivim! :nerd_face:
https://on...
New
If you are experiencing Rails console using 100% CPU on your dev machine, then updating your development and test gems might fix the issu...
New
Use WebRTC to build web applications that stream media and data in real time directly from one user to another, all in the browser.
...
New
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
Will Swifties’ war on AI fakes spark a deepfake porn reckoning?
New
This is cool!
DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON
We just witnessed something incredible: the largest open-s...
New
This is a very quick guide, you just need to:
Download LM Studio: https://lmstudio.ai/
Click on search
Type DeepSeek, then select the o...
New
A concise guide to MySQL 9 database administration, covering fundamental concepts, techniques, and best practices.
Neil Smyth
MySQL...
New
Categories:
Sub Categories:
Popular Portals
- /elixir
- /rust
- /ruby
- /wasm
- /erlang
- /phoenix
- /keyboards
- /python
- /js
- /rails
- /security
- /go
- /swift
- /vim
- /clojure
- /emacs
- /haskell
- /java
- /svelte
- /onivim
- /typescript
- /kotlin
- /c-plus-plus
- /crystal
- /tailwind
- /react
- /gleam
- /ocaml
- /elm
- /flutter
- /vscode
- /ash
- /html
- /opensuse
- /centos
- /php
- /zig
- /deepseek
- /scala
- /sublime-text
- /lisp
- /textmate
- /react-native
- /nixos
- /debian
- /agda
- /kubuntu
- /arch-linux
- /deno
- /django
- /revery
- /ubuntu
- /nodejs
- /spring
- /manjaro
- /diversity
- /lua
- /julia
- /slackware
- /c







