add test case for Records (used in HostBalancer)

- simulating seek error (http://mantis.tokeek.de/view.php?id=411)

test/net/yacy/kelondro/io/RecordsTest.java

@@ -0,0 +1,52 @@
+
+package net.yacy.kelondro.io;
+
+import java.io.File;
+import net.yacy.cora.document.encoding.ASCII;
+import static org.junit.Assert.assertEquals;
+import org.junit.Test;
+
+
+public class RecordsTest {
+
+    final String tesDir = "test/DATA/INDEX/QUEUE";
+
+    /**
+     * Test of cleanLast method, of class Records.
+     */
+    @Test
+    public void testCleanLast_byteArr_int() throws Exception {
+
+        File tablefile = new File(tesDir, "test.stack");
+
+        byte[] b = ASCII.getBytes("testDataString");
+        Records rec = new Records(tablefile, b.length);
+
+        rec.add(b, 0); // add some data
+
+        for (int i = 0; i < 5; i++) { // multiple cleanlast
+            rec.cleanLast(b, 0);
+        }
+        assertEquals(0,rec.size());
+        rec.close();
+    }
+
+    /**
+     * Test of cleanLast method, of class Records.
+     */
+    @Test
+    public void testCleanLast() throws Exception {
+        
+        File tablefile = new File (tesDir,"test.stack");
+
+        byte[] b = ASCII.getBytes("testdata");
+        Records rec = new Records(tablefile, b.length);
+
+        rec.add(b, 0); // add data
+        for (int i = 0; i < 5; i++) { // multiple cleanLast
+            rec.cleanLast();
+        }
+        assertEquals(0,rec.size());
+        rec.close();
+    }
+}