diff --git a/src/test/java/j8583/CustomBinCodecs.java b/src/test/java/j8583/CustomBinCodecs.java
new file mode 100644
index 0000000..c4a4103
--- /dev/null
+++ b/src/test/java/j8583/CustomBinCodecs.java
@@ -0,0 +1,50 @@
+package j8583;
+
+import com.solab.iso8583.codecs.BigIntBcdCodec;
+import com.solab.iso8583.codecs.LongBcdCodec;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.math.BigInteger;
+
+/**
+ * Unit tests for the numeric CustomBinaryField codecs.
+ *
+ * @author Enrique Zamudio
+ *         Date: 07/05/13 13:20
+ */
+public class CustomBinCodecs {
+
+    @Test
+    public void testLongCodec() {
+        final LongBcdCodec longCodec = new LongBcdCodec();
+        final byte[] data1 = new byte[]{ 1, 0x23, 0x45, (byte)0x67, (byte)0x89, 00, 00, 00, 00, 00 };
+        final byte[] data2 = new byte[]{ 0x12, 0x34, 0x56, 0x78, (byte)0x90, 00, 00, 00, 00, 00 };
+        Assert.assertEquals(123456789l, (long) longCodec.decodeBinaryField(data1, 0, 5));
+        Assert.assertEquals(1234567890l, (long)longCodec.decodeBinaryField(data2, 0, 5));
+        final byte[] cod1 = longCodec.encodeBinaryField(123456789l);
+        final byte[] cod2 = longCodec.encodeBinaryField(1234567890l);
+        for (int i = 0; i < 5; i++) {
+            Assert.assertEquals("LONG Data1 differs at pos " + i, data1[i], cod1[i]);
+            Assert.assertEquals("LONG Data2 differs at pos " + i, data2[i], cod2[i]);
+        }
+    }
+
+    @Test
+    public void testBigIntCodec() {
+        final BigInteger b29 = new BigInteger("12345678901234567890123456789");
+        final BigInteger b30 = new BigInteger("123456789012345678901234567890");
+        final BigIntBcdCodec bigintCodec = new BigIntBcdCodec();
+        final byte[] data1 = new byte[]{ 1, 0x23, 0x45, 0x67, (byte)0x89, 1, 0x23, 0x45, 0x67, (byte)0x89, 1, 0x23, 0x45, 0x67, (byte)0x89, 00, 00, 00, 00, 00 };
+        final byte[] data2 = new byte[]{ 0x12, 0x34, 0x56, 0x78, (byte)0x90, 0x12, 0x34, 0x56, 0x78, (byte)0x90, 0x12, 0x34, 0x56, (byte)0x78, (byte)0x90, 00, 00, 00, 00, 00 };
+        Assert.assertEquals(b29, bigintCodec.decodeBinaryField(data1, 0, 15));
+        Assert.assertEquals(b30, bigintCodec.decodeBinaryField(data2, 0, 15));
+        final byte[] cod1 = bigintCodec.encodeBinaryField(b29);
+        final byte[] cod2 = bigintCodec.encodeBinaryField(b30);
+        for (int i = 0; i < 15; i++) {
+            Assert.assertEquals("BIGINT Data1 differs at pos " + i, data1[i], cod1[i]);
+            Assert.assertEquals("BIGINT Data2 differs at pos " + i, data2[i], cod2[i]);
+        }
+    }
+
+}