diff -r 251d0ed461fb -r 58ec6da75f6f task4/solution12/test/org/apidesign/apifest08/test/Task1Test.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/task4/solution12/test/org/apidesign/apifest08/test/Task1Test.java	Sat Oct 11 23:38:46 2008 +0200
@@ -0,0 +1,174 @@
+package org.apidesign.apifest08.test;
+
+import java.util.Currency;
+
+import junit.framework.TestCase;
+
+import org.apidesign.apifest08.currency.Convertor;
+import org.apidesign.apifest08.currency.exceptions.InvalidCurrencyException;
+import org.apidesign.apifest08.currency.exceptions.UnknownConvertorException;
+
+/**
+ * Finish the Convertor API, and then write bodies of methods inside of this class to match the given tasks. To fullfil
+ * your task, use the API define in the <code>org.apidesign.apifest08.currency</code> package. Do not you reflection, or
+ * other hacks as your code shall run without any runtime permissions.
+ */
+public class Task1Test extends TestCase {
+  public Task1Test(String testName) {
+    super(testName);
+  }
+
+  @Override
+  protected void setUp() throws Exception {
+  }
+
+  @Override
+  protected void tearDown() throws Exception {
+  }
+
+  //
+  // Imagine that there are three parts of the whole system:
+  // 1. there is someone who knows the current exchange rate
+  // 2. there is someone who wants to do the conversion
+  // 3. there is the API between 1. and 2. which allows them to communicate
+  // Please design such API
+  //
+
+  /**
+   * Create convertor that understands two currencies, CZK and USD. Make 1 USD == 17 CZK. This is a method provided for
+   * #1 group - e.g. those that know the exchange rate. They somehow need to create the objects from the API and tell
+   * them the exchange rate. The API itself knows nothing about any rates, before the createCZKtoUSD method is called.
+   * Creation of the convertor shall not require subclassing of any class or interface on the client side.
+   * @return prepared convertor ready for converting USD to CZK and CZK to USD
+   */
+  public static Convertor createCZKtoUSD() {
+    // set exchange rates
+    Convertor.setConvertorRates(Currency.getInstance("USD"), Currency.getInstance("CZK"), 17d, 1d);
+
+    // create new instance
+    Convertor convertor = null;
+    try {
+      convertor = Convertor.getConvertorInstance(Currency.getInstance("USD"), Currency.getInstance("CZK"));
+    } catch (UnknownConvertorException e) {
+      e.printStackTrace();
+    }
+
+    return convertor;
+  }
+
+  /**
+   * Create convertor that understands two currencies, CZK and SKK. Make 100 SKK == 80 CZK. Again this is method for the
+   * #1 group - it knows the exchange rate, and needs to use the API to create objects with the exchange rate. Anyone
+   * shall be ready to call this method without any other method being called previously. The API itself shall know
+   * nothing about any rates, before this method is called. Creation of the convertor shall not require subclassing of
+   * any class or interface on the client side.
+   * @return prepared convertor ready for converting SKK to CZK and CZK to SKK
+   */
+  public static Convertor createSKKtoCZK() {
+    // set exchange rates
+    Convertor.setConvertorRates(Currency.getInstance("SKK"), Currency.getInstance("CZK"), 80d, 100d);
+
+    // create new instance
+    Convertor convertor = null;
+    try {
+      convertor = Convertor.getConvertorInstance(Currency.getInstance("SKK"), Currency.getInstance("CZK"));
+    } catch (UnknownConvertorException e) {
+      e.printStackTrace();
+    }
+
+    return convertor;
+  }
+
+  //
+  // now the methods for group #2 follow:
+  // this group knows nothing about exchange rates, but knows how to use
+  // the API to do conversions. It somehow (by calling one of the factory
+  // methods) gets objects from the API and uses them to do the conversions.
+  //
+
+  /**
+   * Use the convertor from <code>createCZKtoUSD</code> method and do few conversions with it.
+   */
+  public void testCurrencyCZKUSD() throws Exception {
+    Convertor c = createCZKtoUSD();
+    // convert $5 to CZK using c:
+    double result = c.convert(5, Currency.getInstance("USD"), Currency.getInstance("CZK"));
+    assertEquals("Result is not 85 CZK", 85.0, result);
+
+    // convert $8 to CZK
+    result = c.convert(8, Currency.getInstance("USD"), Currency.getInstance("CZK"));
+    assertEquals("Result is not 136 CZK", 136.0, result);
+
+    // convert 1003CZK to USD
+    result = c.convert(1003, Currency.getInstance("CZK"), Currency.getInstance("USD"));
+    assertEquals("Result is not 59 USD", 59.0, result);
+  }
+
+  /**
+   * Use the convertor from <code>createSKKtoCZK</code> method and do few conversions with it.
+   */
+  public void testCurrencySKKCZK() throws Exception {
+    Convertor c = createSKKtoCZK();
+
+    // convert 16CZK using c:
+    double result = c.convert(16, Currency.getInstance("CZK"), Currency.getInstance("SKK"));
+    assertEquals("Result is not 20 SKK", 20.0, result);
+
+    // convert 500SKK to CZK
+    result = c.convert(500, Currency.getInstance("SKK"), Currency.getInstance("CZK"));
+    assertEquals("Result is not 400 CZK", 400.0, result);
+  }
+
+  /**
+   * Verify that the CZK to USD convertor knows nothing about SKK.
+   */
+  public void testCannotConvertToSKKwithCZKUSDConvertor() throws Exception {
+    Convertor c = createCZKtoUSD();
+    boolean exceptionThrown = false;
+
+    // convert $5 to SKK, the API shall say this is not possible
+    try {
+      c.convert(5, Currency.getInstance("USD"), Currency.getInstance("SKK"));
+      exceptionThrown = false;
+    } catch (InvalidCurrencyException e) {
+      exceptionThrown = true;
+    }
+    assertEquals("It should be impossible to convert to SKK with USD->CZK convertor", true, exceptionThrown);
+
+    // convert 500 SKK to CZK, the API shall say this is not possible
+    try {
+      c.convert(500, Currency.getInstance("SKK"), Currency.getInstance("CZK"));
+      exceptionThrown = false;
+    } catch (InvalidCurrencyException e) {
+      exceptionThrown = true;
+    }
+    assertEquals("It should be impossible to convert from SKK with USD->CZK convertor", true, exceptionThrown);
+
+  }
+
+  /**
+   * Verify that the CZK to SKK convertor knows nothing about USD.
+   */
+  public void testCannotConvertToSKKwithSKKCZKConvertor() throws Exception {
+    Convertor c = createSKKtoCZK();
+    boolean exceptionThrown = false;
+
+    // convert $5 to SKK, the API shall say this is not possible
+    try {
+      c.convert(5, Currency.getInstance("USD"), Currency.getInstance("SKK"));
+      exceptionThrown = false;
+    } catch (InvalidCurrencyException e) {
+      exceptionThrown = true;
+    }
+    assertEquals("It should be impossible to convert form USD with SKK->CZK convertor", true, exceptionThrown);
+
+    // convert 500 CZK to USD, the API shall say this is not possible
+    try {
+      c.convert(500, Currency.getInstance("CZK"), Currency.getInstance("USD"));
+      exceptionThrown = false;
+    } catch (InvalidCurrencyException e) {
+      exceptionThrown = true;
+    }
+    assertEquals("It should be impossible to convert to USD with SKK->CZK convertor", true, exceptionThrown);
+  }
+}