Solve c.

Java/src/main/java/org/codecop/dependencies/c/Checkout.java

@@ -10,8 +10,12 @@ public Receipt createReceipt(Money amount) {
         receipt.setTax(vat);
         receipt.setTotal(amount.add(vat));
 
-        ReceiptRepository.store(receipt);
+        store(receipt);
 
         return receipt;
     }
+
+    protected void store(Receipt receipt) {
+        ReceiptRepository.store(receipt);
+    }
 }

Java/src/test/java/org/codecop/dependencies/c/CheckoutTest.java

@@ -1,17 +1,21 @@
 package org.codecop.dependencies.c;
 
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
 
-import static org.junit.Assert.assertNotNull;
+import org.junit.Test;
 
 public class CheckoutTest {
 
     @Test
-    public void test3() {
-        Checkout checkout = new Checkout();
-
-        checkout.createReceipt(new Money(12));
-
-        assertNotNull(checkout);
+    public void createReceipt() {
+        Checkout checkout = new Checkout() {
+            @Override
+            protected void store(Receipt receipt) {
+            }
+        };
+
+        Receipt receipt = checkout.createReceipt(new Money(12));
+
+        assertEquals(new Money("14.4"), receipt.getTotal());
     }
 }