update java/ch12 & ch13 - ch11 with README's and updated libraries.

bgruenba · bgruenba · commit 51c0fba00f80 · 2025-09-21T20:02:10.000-07:00
diff --git a/cs/ch12/README.md b/cs/ch12/README.md
@@ -1,6 +1,6 @@
 # Test-Driven Development - C# - Chapter 12
 
-This solution contains a code for Chapter 12 of the book ["Test-Driven Development By Example" by 
+This solution contains code for Chapter 12 of the book ["Test-Driven Development By Example" by 
 Kent Beck](https://a.co/d/1sr05eT). The code is written in C# and uses the NUnit testing framework for the tests. 
 
 For information on how to set up the repository, please see the [README in the ch00](../ch00/README.md) folder.
diff --git a/cs/ch13/README.md b/cs/ch13/README.md
@@ -1,6 +1,6 @@
 # Test-Driven Development - C# - Chapter 13
 
-This solution contains a code for Chapter 13 of the book ["Test-Driven Development By Example" by 
+This solution contains code for Chapter 13 of the book ["Test-Driven Development By Example" by 
 Kent Beck](https://a.co/d/1sr05eT). The code is written in C# and uses the NUnit testing framework for the tests. 
 
 For information on how to set up the repository, please see the [README in the ch00](../ch00/README.md) folder.
diff --git a/java/ch12/README.md b/java/ch12/README.md
@@ -1,7 +1,7 @@
-# Test-Driven Development - C# - Chapter 12
+# Test-Driven Development - Java - Chapter 12
 
-This solution contains a code for Chapter 12 of the book ["Test-Driven Development By Example" by 
-Kent Beck](https://a.co/d/1sr05eT). The code is written in C# and uses the NUnit testing framework for the tests. 
+This solution contains code for Chapter 12 of the book ["Test-Driven Development By Example" by 
+Kent Beck](https://a.co/d/1sr05eT). The code is written in Java and uses the JUnit testing framework for the tests. 
 
 For information on how to set up the repository, please see the [README in the ch00](../ch00/README.md) folder.
 
@@ -88,10 +88,11 @@ By the end of the chapter, the TODO list looks like this:
 - [x] Delete `testFrancMultiplication()`
 
 ## Last Update
-I try and keep this code up to date with the latest versions. I generally wait until a new version of .NET SDK is 
-released and I only update it for Long Term Support (LTS) versions. .NET 8 is the latest LTS version as of this writing.
+I try and keep this code up to date with the latest versions. I generally wait until a new version of the JDK or Maven is 
+released and I only update it for major versions. JDK 25 is the latest version as of this writing, and the POM is set to
+use JDK 25 and JUnit 5.13.4.
 
 This repository was last updated in September 2025.
-- .NET SDK version 8
-- NUnit version 4.4.0
-- JetBrains Rider version 2025.2.2
+- Java JDK version 25
+- JUnit version 5.13.4
+- JetBrains IntelliJ IDEA Ultimate version 2025.2.2
diff --git a/java/ch12/src/main/java/com/thesoftwaregorilla/tdd/money/Money.java b/java/ch12/src/main/java/com/thesoftwaregorilla/tdd/money/Money.java
@@ -34,8 +34,7 @@ public Expression plus(Money addend) {
 
     @Override
     public boolean equals(Object object) {
-        Money money = (Money) object;
-        return getAmount() == money.getAmount() && getCurrency().equals(money.getCurrency());
+        return object instanceof Money money && this.amount == money.amount && this.currency.equals(money.currency);
     }
 
     @Override
diff --git a/java/ch12/src/test/java/com/thesoftwaregorilla/tdd/money/MoneyTest.java b/java/ch12/src/test/java/com/thesoftwaregorilla/tdd/money/MoneyTest.java
@@ -3,6 +3,26 @@
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.*;
 
+//TODO: $5 + 10 CHF = $10 if rate is 2:1
+//TODO: $5 + $5 = $10
+//TODO: Money rounding?
+//TODO: hashCode()
+//TODO: Equal null
+//TODO: Equal object
+
+//DONE items:
+//TODO: equals() -DONE
+//TODO: $5 * 2 = $10 - DONE 
+//TODO: Make "amount" private - DONE
+//TODO: Dollar side-effects? - DONE
+//TODO: 5 CHF * 2 = 10 CHF - DONE
+//TODO: Dollar/Franc duplication - DONE
+//TODO: Common equals - DONE
+//TODO: Common Times - DONE
+//TODO: Compare Francs with Dollars - DONE
+//TODO: Currency? - DONE
+//TODO: Delete `testFrancMultiplication()` - DONE
+
 public class MoneyTest {
 
     private final Money fiveDollar = Money.dollar(5);
diff --git a/java/ch13/README.md b/java/ch13/README.md
@@ -1,7 +1,7 @@
-# Test-Driven Development - C# - Chapter 13
+# Test-Driven Development - Java - Chapter 13
 
-This solution contains a code for Chapter 13 of the book ["Test-Driven Development By Example" by 
-Kent Beck](https://a.co/d/1sr05eT). The code is written in C# and uses the NUnit testing framework for the tests. 
+This solution contains code for Chapter 13 of the book ["Test-Driven Development By Example" by 
+Kent Beck](https://a.co/d/1sr05eT). The code is written in Java and uses the JUnit testing framework for the tests. 
 
 For information on how to set up the repository, please see the [README in the ch00](../ch00/README.md) folder.
 
@@ -12,14 +12,12 @@ now returns a 'Sum' object. The 'Bank' class is introduced to handle currency co
 given currency.
 
 ### Key point from the chapter
-Two big code changes had to happen in my code in this chapter had to happen:
-1. The `amount` field in the `Money` class needed to be exposed as a property so that it could be accessed from the `Sum`
-   class.
-2. The constructor in the `Money` class needed to be changed to `internal` so that it could be accessed from the `Sum`
-   class.
-   I have a rule that I never want to expose anything that is not absolutely necessary, so I my own TDD approach to this
-   would have been to have more explicit intention about the `Amount` property, and refactor the factory methods in `Money`
-   for the specific implementations. I changed the code here so that the `Amount` property is `public` but `set` is `private`.
+The `amount` field in the `Money` class needed to be exposed as a property so that it could be accessed from the `Sum`
+class. For the Java version of the code, I did that a while back.
+
+I have a rule that I never want to expose anything that is not absolutely necessary, so I my own TDD approach to this
+would have been to have more explicit intention about the `amount` property, and refactor the factory methods in `Money`
+for the specific implementations. I changed the code here so that the `amount` property is `public` but `set` is `private`.
 
 ### My thoughts on the chapter
 This is one of the worst chapters in the book. No matter how many times I read it, I don't understand the premise that
@@ -56,10 +54,11 @@ By the end of the chapter, the TODO list looks like this:
 - [x] Delete `testFrancMultiplication()`
 
 ## Last Update
-I try and keep this code up to date with the latest versions. I generally wait until a new version of .NET SDK is 
-released and I only update it for Long Term Support (LTS) versions. .NET 8 is the latest LTS version as of this writing.
+I try and keep this code up to date with the latest versions. I generally wait until a new version of the JDK or Maven is 
+released and I only update it for major versions. JDK 25 is the latest version as of this writing, and the POM is set to
+use JDK 25 and JUnit 5.13.4.
 
 This repository was last updated in September 2025.
-- .NET SDK version 8
-- NUnit version 4.4.0
-- JetBrains Rider version 2025.2.2
+- Java JDK version 25
+- JUnit version 5.13.4
+- JetBrains IntelliJ IDEA Ultimate version 2025.2.2
diff --git a/java/ch13/src/main/java/com/thesoftwaregorilla/tdd/money/Money.java b/java/ch13/src/main/java/com/thesoftwaregorilla/tdd/money/Money.java
@@ -39,8 +39,7 @@ public Money reduce(String to) {
 
     @Override
     public boolean equals(Object object) {
-        Money money = (Money) object;
-        return getAmount() == money.getAmount() && getCurrency().equals(money.getCurrency());
+        return object instanceof Money money && this.amount == money.amount && this.currency.equals(money.currency);
     }
 
     @Override
diff --git a/java/ch13/src/test/java/com/thesoftwaregorilla/tdd/money/MoneyTest.java b/java/ch13/src/test/java/com/thesoftwaregorilla/tdd/money/MoneyTest.java
@@ -3,6 +3,30 @@
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.*;
 
+//TODO: $5 + 10 CHF = $10 if rate is 2:1
+//TODO: $5 + $5 = $10
+//TODO: Return Money from $5 + $5
+//TODO: Bank.Reduce(Money) - DONE
+//TODO: Reduce Money with conversion
+//TODO: Reduce (Bank, String)
+//TODO: Money rounding?
+//TODO: hashCode()
+//TODO: Equal null
+//TODO: Equal object
+
+//DONE items:
+//TODO: equals() -DONE
+//TODO: $5 * 2 = $10 - DONE 
+//TODO: Make "amount" private - DONE
+//TODO: Dollar side-effects? - DONE
+//TODO: 5 CHF * 2 = 10 CHF - DONE
+//TODO: Dollar/Franc duplication - DONE
+//TODO: Common equals - DONE
+//TODO: Common Times - DONE
+//TODO: Compare Francs with Dollars - DONE
+//TODO: Currency? - DONE
+//TODO: Delete `testFrancMultiplication()` - DONE
+
 public class MoneyTest {
 
     private final Money fiveDollar = Money.dollar(5);

Original file line number	Diff line number	Diff line change
`@@ -34,8 +34,7 @@ public Expression plus(Money addend) {`
`34`	`34`
`35`	`35`	`@Override`
`36`	`36`	`public boolean equals(Object object) {`
`37`		`- Money money = (Money) object;`
`38`		`- return getAmount() == money.getAmount() && getCurrency().equals(money.getCurrency());`
	`37`	`+ return object instanceof Money money && this.amount == money.amount && this.currency.equals(money.currency);`
`39`	`38`	`}`
`40`	`39`
`41`	`40`	`@Override`
Original file line number	Diff line number	Diff line change
`@@ -39,8 +39,7 @@ public Money reduce(String to) {`
`39`	`39`
`40`	`40`	`@Override`
`41`	`41`	`public boolean equals(Object object) {`
`42`		`- Money money = (Money) object;`
`43`		`- return getAmount() == money.getAmount() && getCurrency().equals(money.getCurrency());`
	`42`	`+ return object instanceof Money money && this.amount == money.amount && this.currency.equals(money.currency);`
`44`	`43`	`}`
`45`	`44`
`46`	`45`	`@Override`