Qpid-861: Java RFC 1982 implementation + Junit tests

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@641212 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 135 insertions, 0 deletions

diff --git a/java/common/src/test/java/org/apache/qpid/util/SerialTest.java b/java/common/src/test/java/org/apache/qpid/util/SerialTest.java
new file mode 100644
index 0000000000..312b1ab9ce
--- /dev/null
+++ b/java/common/src/test/java/org/apache/qpid/util/SerialTest.java
@@ -0,0 +1,135 @@
+package org.apache.qpid.util;
+
+import junit.framework.TestCase;
+
+import java.util.Random;
+
+import org.apache.qpid.SerialException;
+
+/**
+ *Junit tests for the Serial class 
+ */
+public class SerialTest extends TestCase
+{
+
+    /**
+     * The simplest meaningful serial number space has SERIAL_BITS == 2.  In
+     * this space, the integers that make up the serial number space are 0,
+     * 1, 2, and 3.  That is, 3 == 2^SERIAL_BITS - 1.
+     *
+     * In this space, the largest integer that it is meaningful to add to a
+     * sequence number is 2^(SERIAL_BITS - 1) - 1, or 1.
+     *
+     * Then, as defined 0+1 == 1, 1+1 == 2, 2+1 == 3, and 3+1 == 0.
+     * Further, 1 > 0, 2 > 1, 3 > 2, and 0 > 3.  It is undefined whether
+     * 2 > 0 or 0 > 2, and whether 1 > 3 or 3 > 1.
+     */
+    public void testTrivialSample()
+    {
+        Serial serial = new Serial(2);
+        assertEquals( serial.increment(0, 1), 1);
+        assertEquals( serial.increment(1, 1), 2);
+        assertEquals( serial.increment(2, 1), 3);
+        assertEquals( serial.increment(3, 1), 0);
+        try
+        {
+            serial.increment(4, 1);
+            fail("IllegalArgumentException was not trhown");
+        }
+        catch (IllegalArgumentException e)
+        {
+           // expected
+        }
+        try
+        {
+            assertTrue( serial.compare(1, 0) > 0);
+            assertTrue( serial.compare(2, 1) > 0);
+            assertTrue( serial.compare(3, 2) > 0);
+            assertTrue( serial.compare(0, 3) > 0);
+            assertTrue( serial.compare(0, 1) < 0);
+            assertTrue( serial.compare(1, 2) < 0);
+            assertTrue( serial.compare(2, 3) < 0);
+            assertTrue( serial.compare(3, 0) < 0);
+        }
+        catch (SerialException e)
+        {
+            fail("Unexpected exception " + e);
+        }
+        try
+        {
+            serial.compare(2, 0);
+            fail("AMQSerialException not thrown as expected");
+        }
+        catch (SerialException e)
+        {
+           // expected
+        }
+        try
+        {
+            serial.compare(0, 2);
+            fail("AMQSerialException not thrown as expected");
+        }
+        catch (SerialException e)
+        {
+           // expected
+        }
+        try
+        {
+            serial.compare(3, 1);
+            fail("AMQSerialException not thrown as expected");
+        }
+        catch (SerialException e)
+        {
+           // expected
+        }
+        try
+        {
+            serial.compare(3, 1);
+            fail("AMQSerialException not thrown as expected");
+        }
+        catch (SerialException e)
+        {
+           // expected
+        }
+    }
+
+    /**
+     * Test the first Corollary of RFC 1982
+     * For any sequence number s and any integer n such that addition of n
+     * to s is well defined, (s + n) >= s.  Further (s + n) == s only when
+     * n == 0, in all other defined cases, (s + n) > s.
+     * strategy:
+     * Create a serial number with 32 bits and check in a loop that adding integers
+     * respect the corollary
+     */
+    public void testCorollary1()
+    {
+        Serial serial = new Serial(32);
+        Random random = new Random();
+        long number = random.nextInt((int) Math.pow(2.0 , 32.0) - 1);
+        for(int i = 1; i<= 10000; i++ )
+        {
+           long nextInt = random.nextInt((int) Math.pow(2.0 , 32.0) - 1);
+           long inc = serial.increment(number, nextInt);
+            int res =0;
+            try
+            {
+                res=serial.compare(inc, number);
+            }
+            catch (SerialException e)
+            {
+                fail("un-expected exception " + e);
+            }
+            if( res < 1 )
+            {
+               fail("Corollary 1 violated " + number + " + " + nextInt + " < " + number);
+            }
+            else if( res == 0 && nextInt > 0)
+            {
+               fail("Corollary 1 violated " + number + " + " + nextInt + " = " + number);
+            }
+        }
+    }
+
+    
+}