diff -r 14e78f48ac2b -r 58ec6da75f6f task4/solution04/test/org/apidesign/apifest08/test/TestExchangeRateFinder.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/task4/solution04/test/org/apidesign/apifest08/test/TestExchangeRateFinder.java	Sat Oct 11 23:38:46 2008 +0200
@@ -0,0 +1,61 @@
+package org.apidesign.apifest08.test;
+
+
+import java.math.BigDecimal;
+import java.util.Currency;
+import org.apidesign.apifest08.currency.ExchangeRate;
+import org.apidesign.apifest08.currency.ExchangeRateFinder;
+
+
+class TestExchangeRateFinder
+    implements ExchangeRateFinder
+{
+    private final BigDecimal min;
+    private final BigDecimal max;
+    private final BigDecimal stepUp;
+    private final BigDecimal stepDown;
+    private BigDecimal step;
+    private BigDecimal rate;
+    private boolean firstCall;
+
+    TestExchangeRateFinder(final BigDecimal mn,
+                           final BigDecimal mx,
+                           final BigDecimal start,
+                           final BigDecimal up,
+                           final BigDecimal down)
+    {
+        min       = mn;
+        max       = mx;
+        rate      = start;
+        stepUp    = up;
+        stepDown  = down;
+        firstCall = true;
+    }
+    
+    public ExchangeRate findRate(Currency a, Currency b) 
+    {
+        final ExchangeRate value;
+
+        if(rate.equals(max))
+        {
+            step = stepDown;
+        }
+        else if(rate.equals(min))
+        {
+            step = stepUp;
+        }
+
+        value = new ExchangeRate(a, b, BigDecimal.ONE, rate);
+
+        if(firstCall)
+        {
+            firstCall = false;
+        }
+        else
+        {
+            rate = rate.add(step);
+        }
+
+        return (value);
+    }
+}