test

.classpath

@@ -31,6 +31,19 @@
 			<attribute name="m2e-apt" value="true"/>
 		</attributes>
 	</classpathentry>
+	<classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="optional" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry excluding="**" kind="src" output="target/test-classes" path="src/test/resources">
+		<attributes>
+			<attribute name="maven.pomderived" value="true"/>
+			<attribute name="test" value="true"/>
+			<attribute name="optional" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="src" output="target/test-classes" path="target/generated-test-sources/test-annotations">
 		<attributes>
 			<attribute name="optional" value="true"/>

.project

@@ -20,4 +20,15 @@
 		<nature>org.eclipse.jdt.core.javanature</nature>
 		<nature>org.eclipse.m2e.core.maven2Nature</nature>
 	</natures>
+	<filteredResources>
+		<filter>
+			<id>1685771014683</id>
+			<name></name>
+			<type>30</type>
+			<matcher>
+				<id>org.eclipse.core.resources.regexFilterMatcher</id>
+				<arguments>node_modules|\.git|__CREATED_BY_JAVA_LANGUAGE_SERVER__</arguments>
+			</matcher>
+		</filter>
+	</filteredResources>
 </projectDescription>

.settings/org.eclipse.core.resources.prefs

@@ -0,0 +1,4 @@
+eclipse.preferences.version=1
+encoding//src/main/java=UTF-8
+encoding//src/test/java=UTF-8
+encoding/<project>=UTF-8

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+    "java.debug.settings.onBuildFailureProceed": true
+}

src/main/java/com/mycompany/fibonacci/FibonacciTest.java

@@ -0,0 +1,7 @@
+package com.mycompany.fibonacci;
+
+public class FibonacciTest {
+    int fib(int n){
+        return 0;
+    }
+}

src/main/java/com/mycompany/money/Bank.java

@@ -0,0 +1,18 @@
+package com.mycompany.money;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class Bank {
+    private Map<Pair, Integer> rates = new HashMap<>();
+    Money reduce(Expression source, String to){
+        return source.reduce(this, to);
+    }
+    void addRate(String from, String to, int rate){
+        rates.put(new Pair(from, to), rate);
+    }
+    int rate(String from, String to){
+        if(from.equals(to)) return 1;
+        return rates.get(new Pair(from, to));
+    }
+}

src/main/java/com/mycompany/money/Expression.java

@@ -0,0 +1,5 @@
+package com.mycompany.money;
+
+public interface Expression {
+    Money reduce(Bank bank, String to);
+}

src/main/java/com/mycompany/money/Money.java

@@ -0,0 +1,46 @@
+package com.mycompany.money;
+
+class Money implements Expression {
+    protected int amount;
+    protected String currency;
+
+    Money(int amount, String currency) {
+        this.amount = amount;
+        this.currency = currency;
+    }
+
+    Money times(int multiplier) {
+        return new Money(amount * multiplier, currency);
+    };
+
+    Expression plus(Money addend) {
+        return new Sum(this, addend);
+    }
+
+    public Money reduce(Bank bank, String to) {
+        int rate = bank.rate(currency, to);
+        return new Money(amount / rate, to);
+    }
+
+    String currency() {
+        return currency;
+    }
+
+    public boolean equals(Object object) {
+        Money money = (Money) object;
+        return amount == money.amount
+                && currency().equals(money.currency());
+    }
+
+    public String toString() {
+        return amount + " " + currency;
+    }
+
+    static Money dollar(int amount) {
+        return new Money(amount, "USD");
+    }
+
+    static Money franc(int amount) {
+        return new Money(amount, "CHF");
+    }
+}

src/main/java/com/mycompany/money/Pair.java

@@ -0,0 +1,17 @@
+package com.mycompany.money;
+
+public class Pair {
+    private String from;
+    private String to;
+    Pair(String from, String to){
+        this.from = from;
+        this.to = to;
+    }
+    public boolean equals(Object object){
+        Pair pair = (Pair) object;
+        return from.equals(pair.from) && to.equals(pair.to);
+    }
+    public int hashCode(){
+        return 0;
+    }
+}

src/main/java/com/mycompany/money/Sum.java

@@ -0,0 +1,14 @@
+package com.mycompany.money;
+
+public class Sum implements Expression{
+    Money augend;
+    Money addend;
+    Sum(Money augend, Money addend){
+        this.augend = augend;
+        this.addend = addend;
+    }
+    public Money reduce(Bank bank, String to){
+        int amount = augend.reduce(bank, to).amount + addend.reduce(bank, to).amount;
+        return new Money(amount, to);
+    }
+}

src/test/java/com/mycompany/fibonacci/FibonacciTest.java

@@ -0,0 +1,16 @@
+package com.mycompany.fibonacci;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+public class FibonacciTest {
+    int fib(int n){
+        return 0;
+    }
+    @Test
+    public void testFibonacci() {
+        assertEquals(0, fib(0));
+        assertEquals(1, fib(1));
+    }
+}

src/test/java/com/mycompany/money/MoneyTest.java

@@ -0,0 +1,85 @@
+package com.mycompany.money;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class MoneyTest {
+    @Test
+    public void testMultiplication() {
+        Money five = Money.dollar(5);
+        assertEquals(Money.dollar(10), five.times(2));
+        assertEquals(Money.dollar(15), five.times(3));
+    }
+
+    @Test
+    public void testEquality() {
+        assertTrue(Money.dollar(5).equals(Money.dollar(5)));
+        assertFalse(Money.dollar(5).equals(Money.dollar(6)));
+        assertFalse(Money.franc(5).equals(Money.dollar(5)));
+    }
+
+    @Test
+    public void testCurrency() {
+        assertEquals("USD", Money.dollar(1).currency());
+        assertEquals("CHF", Money.franc(1).currency());
+    }
+
+    @Test
+    public void testSimpleAddition() {
+        Money five = Money.dollar(5);
+        Expression sum = five.plus(five);
+        Bank bank = new Bank();
+        Money reduced = bank.reduce(sum, "USD");
+        assertEquals(Money.dollar(10), reduced);
+    }
+
+    @Test
+    public void testPlusReturnsSum() {
+        Money five = Money.dollar(5);
+        Expression result = five.plus(five);
+        Sum sum = (Sum) result;
+        assertEquals(five, sum.augend);
+        assertEquals(five, sum.addend);
+    }
+
+    @Test
+    public void testReduceSum() {
+        Expression sum = new Sum(Money.dollar(3), Money.dollar(4));
+        Bank bank = new Bank();
+        Money result = bank.reduce(sum, "USD");
+        assertEquals(Money.dollar(7), result);
+    }
+
+    @Test
+    public void testReduceMoney() {
+        Bank bank = new Bank();
+        Money result = bank.reduce(Money.dollar(1), "USD");
+        assertEquals(Money.dollar(1), result);
+    }
+
+    @Test
+    public void testReduceMoneyDifferentCurrency() {
+        Bank bank = new Bank();
+        bank.addRate("CHF", "USD", 2);
+        Money result = bank.reduce(Money.franc(2), "USD");
+        assertEquals(Money.dollar(1), result);
+    }
+
+    @Test
+    public void testIdentityRate() {
+        assertEquals(1, new Bank().rate("USD", "USD"));
+    }
+
+    @Test
+    public void testMixedAddition() {
+        Money fiveBucks = Money.dollar(5);
+        Money tenFrancs = Money.franc(10);
+        Bank bank = new Bank();
+        bank.addRate("CHF", "USD", 2);
+        Money result = bank.reduce(fiveBucks.plus(tenFrancs), "USD");
+        assertEquals(Money.dollar(10), result);
+    }
+}