dtonhofer
Functional Programming in Java, Second Edition: p.90 CalculateNAVTest erroneous
On page 90, CalculateNAVTest.java:
public class CalculateNAVTest {
@Test
public void computeStockWorth() {
final CalculateNAV calculateNAV = new CalculateNAV(ticker -> new BigDecimal("6.01"));
BigDecimal expected = new BigDecimal("6010.00");
assertEquals(0, calculateNAV.computeStockWorth("GOOG", 1000).compareTo(expected), 0.001);
}
The assertEquals() makes no sense.
It runs BigDecimal.compare( new BigDecimal("6010") , new BigDecimal("6010.00") ) which is either -1, 0 or +1, and compares it with 0 with an irrelevant precision of 0.001.
What we want is:
public class CalculateNAVTest {
@Test
public void computeStockWorth() {
final CalculateNAV calculateNAV = new CalculateNAV(ticker -> new BigDecimal("6.01"));
BigDecimal expected = new BigDecimal("6010.00");
BigDecimal actual = calculateNAV.computeStockWorth("GOOG", 1000);
BigDecimal delta = actual.subtract(expected);
assertEquals(delta.doubleValue(), 0, 0.001);
}
JavaDoc for BigDecimal.compare():
Marked As Solved
venkats
Author of Programming Kotlin, Rediscovering JavaScript (and 6 other titles)
Very good catch. Fixed. Thank you.
1
Popular Pragmatic Bookshelf topics
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks”
While running the smoke tests in Chapter 2, I get these...
New
Hello Brian,
I have some problems with running the code in your book. I like the style of the book very much and I have learnt a lot as...
New
Hi,
build fails on:
bracket-lib = “~0.8.1”
when running on Mac Mini M1 Rust version 1.5.0:
Compiling winit v0.22.2
error[E0308]: mi...
New
First, the code resources:
Page 237: rumbl_umbrella/apps/rumbl/mix.exs
Note: That this file is missing.
Page 238: rumbl_umbrella/app...
New
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
The book has the same “Problem space/Solution space” diagram on page 18 as is on page 17. The correct Problem/Solution space diagrams ar...
New
Is there any place where we can discuss the solutions to some of the exercises? I can figure most of them out, but am having trouble with...
New
It seems the second code snippet is missing the code to set the current_user:
current_user: Accounts.get_user_by_session_token(session["...
New
@parrt
In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
New
root_layout: {PentoWeb.LayoutView, :root},
This results in the following following error:
no “root” html template defined for PentoWeb...
New
Other popular topics
Brace yourself for a fun challenge: build a photorealistic 3D renderer from scratch! In just a couple of weeks, build a ray tracer that r...
New
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
No chair. I have a standing desk.
This post was split into a dedicated thread from our thread about chairs :slight_smile:
New
New
My first contact with Erlang was about 2 years ago when I used RabbitMQ, which is written in Erlang, for my job. This made me curious and...
New
I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...
New
Author Spotlight:
Peter Ullrich
@PJUllrich
Data is at the core of every business, but it is useless if nobody can access and analyze ...
New
Big O Notation can make your code faster by orders of magnitude. Get the hands-on info you need to master data structures and algorithms ...
New
Hello,
I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
Hair Salon Games for Girls Fun
Girls Hair Saloon game is mainly developed for kids. This game allows users to select virtual avatars to ...
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
- /opensuse
- /html
- /centos
- /php
- /zig
- /deepseek
- /scala
- /lisp
- /sublime-text
- /textmate
- /react-native
- /nixos
- /debian
- /agda
- /kubuntu
- /arch-linux
- /deno
- /django
- /revery
- /ubuntu
- /nodejs
- /spring
- /manjaro
- /diversity
- /lua
- /julia
- /c
- /slackware







