added some tests to catalog and shopping cart tests

pom.xml

@@ -29,8 +29,14 @@
       <artifactId>assertj-core</artifactId>
       <version>3.18.0</version>
     </dependency>
+    <dependency>
+      <groupId>org.hamcrest</groupId>
+      <artifactId>hamcrest-all</artifactId>
+      <version>1.3</version>
+     </dependency>
   </dependencies>
 
+
   <build>
     <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
       <plugins>

src/main/java/com/serenitydojo/fruitmarket/Catalog.java

@@ -1,7 +1,9 @@
 package com.serenitydojo.fruitmarket;
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 public class Catalog {
 
@@ -11,8 +13,19 @@ public PriceSetter setPriceOf(Fruit fruit) {
         return new PriceSetter(this, fruit);
     }
 
+    public List<String> getAvailableFruit() {
+        return pricePerKilo.keySet()
+                .stream()
+                .map(Enum::name)
+                .sorted()
+                .collect(Collectors.toList());
+    }
+
     public Double getPriceOf(Fruit fruit) {
-        return pricePerKilo.get(fruit);
+        if (pricePerKilo.containsKey(fruit)) {
+            return pricePerKilo.get(fruit);
+        }
+        throw new FruitUnavailableException(fruit.name() + " currently unavailable");
     }
 
     public static class PriceSetter {

src/main/java/com/serenitydojo/fruitmarket/FruitUnavailableException.java

@@ -0,0 +1,9 @@
+package com.serenitydojo.fruitmarket;
+
+public class FruitUnavailableException extends RuntimeException {
+    public FruitUnavailableException(String message) {
+        super(message);
+    }
+
+
+}

src/main/java/com/serenitydojo/fruitmarket/ShoppingCart.java

@@ -11,4 +11,36 @@ public ShoppingCart(Catalog catalog) {
         this.catalog = catalog;
         this.items = new ArrayList<>();
     }
+
+    public ShoppingCartAdder add(Double amount) {
+        return new ShoppingCartAdder(this, amount);
+    }
+
+
+    public List<ShoppingCartItem> getItems() {
+        return new ArrayList<>(items);
+    }
+
+    public Double getTotalPrice() {
+        return items.stream().mapToDouble(ShoppingCartItem::getTotalCost).sum();
+    }
+
+    public class ShoppingCartAdder {
+        private final ShoppingCart shoppingCart;
+        private final Double amount;
+
+        public ShoppingCartAdder(ShoppingCart shoppingCart, Double amount) {
+            this.shoppingCart = shoppingCart;
+            this.amount = amount;
+        }
+
+        public ShoppingCart kilosOf(Fruit fruit) {
+            double basePrice = shoppingCart.catalog.getPriceOf(fruit);
+            double discountedPrice = (amount >= 5) ? basePrice * 0.9 : basePrice;
+            ShoppingCartItem item = new ShoppingCartItem(fruit, amount, discountedPrice * amount);
+            shoppingCart.items.add(item);
+            return shoppingCart;
+        }
+    }
+
 }

src/test/java/com/serenitydojo/fruitmarket/TheCatalog.java

@@ -1,11 +1,22 @@
 package com.serenitydojo.fruitmarket;
 
+import org.junit.Before;
 import org.junit.Test;
 
 import static com.serenitydojo.fruitmarket.Fruit.*;
 import static org.assertj.core.api.Assertions.assertThat;
 
 public class TheCatalog {
+    Catalog catalog;
+
+    @Before
+    public void createANewCatalog(){
+        catalog = new Catalog();
+        catalog.setPriceOf(Apple).to(4.00)
+                .setPriceOf(Orange).to(5.50)
+                .setPriceOf(Banana).to(4.50)
+                .setPriceOf(Pear).to(4.50);
+    }
 
     @Test
     public void shouldBeAbleToUpdateTheCurrentPriceOfAFruit() {
@@ -14,4 +25,56 @@ public void shouldBeAbleToUpdateTheCurrentPriceOfAFruit() {
         catalog.setPriceOf(Apple).to(4.00);
         assertThat(catalog.getPriceOf(Apple)).isEqualTo(4.00);
     }
+
+    @Test
+    public void shouldListTheAvailableFruitInAlphabeticalOrder() {
+        assertThat(catalog.getAvailableFruit()).containsExactly("Apple", "Banana", "Orange", "Pear");
+
+    }
+
+    @Test
+    public void shouldReturnTheCorrectPricesOfEachFruitInSeason(){
+        assertThat(catalog.getPriceOf(Apple)).isEqualTo(4.00);
+        assertThat(catalog.getPriceOf(Orange)).isEqualTo(5.50);
+       }
+
+    @Test(expected = FruitUnavailableException.class)
+    public void shouldReportAnExceptionIfAFruitIsNotAvailable() {
+        catalog.getPriceOf(Strawberries);
+    }
+
+    //Test I added
+    @Test
+    public void shouldNotBeAbleToAddFruitWithWrongPrice(){
+        Catalog catalog = new Catalog();
+
+        catalog.setPriceOf(Banana).to(4.25);
+
+        assertThat(catalog.getPriceOf(Banana)).isNotEqualTo(4.50);
+    }
+
+    //Test I added
+    @Test
+    public void shouldListAllAvailableFruits(){
+        catalog = new Catalog();
+        catalog.setPriceOf(Apple).to(4.00)
+                .setPriceOf(Orange).to(5.50)
+                .setPriceOf(Banana).to(4.50)
+                .setPriceOf(Pear).to(4.50)
+                .setPriceOf(Peach).to(3.25)
+                .setPriceOf(Strawberries).to(4.25)
+                .setPriceOf(Mulberries).to(3.0);
+
+
+
+        assertThat(catalog.getAvailableFruit()).containsExactlyInAnyOrder("Apple", "Banana",  "Pear","Orange","Mulberries","Peach", "Strawberries");
+
+
+
+
+
+
+
+    }
+
 }

src/test/java/com/serenitydojo/fruitmarket/TheShoppingCart.java

@@ -0,0 +1,87 @@
+package com.serenitydojo.fruitmarket;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static com.serenitydojo.fruitmarket.Fruit.*;
+import static org.assertj.core.api.Assertions.assertThat;
+
+
+public class TheShoppingCart {
+
+    Catalog catalog;
+    ShoppingCart cart;
+
+    @Before
+    public void setupCatalog() {
+        catalog = new Catalog();
+        catalog.setPriceOf(Apple).to(4.00)
+                .setPriceOf(Orange).to(5.50)
+                .setPriceOf(Banana).to(4.50)
+                .setPriceOf(Pear).to(4.50);
+
+        cart = new ShoppingCart(catalog);
+    }
+
+    @Test
+    public void shouldStartWithNoItems() {
+        assertThat(cart.getItems()).isEmpty();
+    }
+
+    @Test
+    public void shouldKeepTrackOfItemsAddedToTheCart() {
+        cart.add(2.0).kilosOf(Apple)
+                .add(3.0).kilosOf(Orange);
+
+        assertThat(cart.getItems()).hasSize(2);
+    }
+
+    @Test
+    public void shouldUseTheCatalogToCalculateThePriceOfItemsAddedToTheCart() {
+        cart.add(2.0).kilosOf(Apple)
+                .add(2.0).kilosOf(Orange)
+                .add(1.0).kilosOf(Pear);
+
+        assertThat(cart.getTotalPrice()).isEqualTo(23.50);
+    }
+
+    @Test
+    public void shouldKeepTrackOfTheTotalPrice() {
+        cart.add(2.0).kilosOf(Apple);
+
+        ShoppingCartItem apples = cart.getItems().get(0);
+
+        assertThat(apples.getFruit()).isEqualTo(Apple);
+        assertThat(apples.getQuantity()).isEqualTo(2.0);
+        assertThat(apples.getTotalCost()).isEqualTo(8.00);
+    }
+
+    @Test
+    public void shouldGiveBulkDiscountsDiscount() {
+        cart.add(10.0).kilosOf(Apple);
+
+        assertThat(cart.getTotalPrice()).isEqualTo(36.00);
+    }
+
+    @Test
+    public void buildDiscountsOnlyApplyToQuantitiesOverFiveKgs() {
+        cart.add(10.0).kilosOf(Apple);
+        cart.add(2.00).kilosOf(Orange);
+
+        assertThat(cart.getTotalPrice()).isEqualTo(47.00);
+    }
+
+//    Test I added
+    @Test
+    public void shouldNotAllowNegativeBalance(){
+        cart.add(10.0).kilosOf(Apple);
+        cart.add(2.00).kilosOf(Orange);
+
+        assertThat(cart.getTotalPrice()).isNotEqualTo(-51.0);
+
+    }
+
+
+
+
+}