node-name needs to be truncated because the byte array is not base64

Add unit test, stress test commented

extensions/narayana-jta/runtime/pom.xml

@@ -83,6 +83,17 @@
             <groupId>org.jboss.narayana.jts</groupId>
             <artifactId>narayana-jts-integration</artifactId>
         </dependency>
+        <!-- Test Dependencies -->
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-junit5-internal</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

extensions/narayana-jta/runtime/src/main/java/io/quarkus/narayana/jta/runtime/NarayanaJtaRecorder.java

@@ -5,6 +5,7 @@
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
+import java.util.Base64;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
@@ -57,9 +58,19 @@ private static void shortenNodeName(TransactionManagerConfiguration transactions
         String originalNodeName = transactions.nodeName;
         log.warnf("Node name \"%s\" is longer than 28 bytes, shortening it by using %s.", originalNodeName,
                 HASH_ALGORITHM_FOR_SHORTENING);
-        final byte[] nodeNameAsBytes = originalNodeName.getBytes();
+        final byte[] nodeNameAsBytes = originalNodeName.getBytes(StandardCharsets.UTF_8);
         MessageDigest messageDigest224 = MessageDigest.getInstance(HASH_ALGORITHM_FOR_SHORTENING);
-        transactions.nodeName = new String(messageDigest224.digest(nodeNameAsBytes), StandardCharsets.UTF_8);
+        byte[] hashedByteArray = messageDigest224.digest(nodeNameAsBytes);
+
+        //Each Base64 digit represents 6 bits of data
+        //encoding the array might result in a longer array
+        //this is needed to guarantee that the resulting string has a deterministic and limited length,
+        //and the conversion is reversible
+        byte[] base64Result = Base64.getEncoder().encode(hashedByteArray);
+        //truncate the array
+        byte[] slice = Arrays.copyOfRange(base64Result, 0, 27);
+
+        transactions.nodeName = new String(slice, StandardCharsets.UTF_8);
         log.warnf("New node name is \"%s\"", transactions.nodeName);
     }
 

extensions/narayana-jta/runtime/src/test/java/io/quarkus/narayana/jta/runtime/NarayanaJtaRecorderTest.java

@@ -0,0 +1,62 @@
+package io.quarkus.narayana.jta.runtime;
+
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.nio.charset.StandardCharsets;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import java.util.UUID;
+
+import org.junit.jupiter.api.Test;
+
+public class NarayanaJtaRecorderTest {
+
+    @Test
+    void testByteLength() {
+
+        TransactionManagerConfiguration transactions = new TransactionManagerConfiguration();
+        transactions.shortenNodeNameIfNecessary = true;
+        // create nodeNames larger than 28 bytes
+        for (int i = 1; i < 100; i++) {
+            String originalNodeName = UUID.randomUUID().toString();
+            NarayanaJtaRecorder r = new NarayanaJtaRecorder();
+            transactions.nodeName = originalNodeName;
+            r.setNodeName(transactions);
+            int numberOfBytes = transactions.nodeName.getBytes(StandardCharsets.UTF_8).length;
+            if (numberOfBytes > 28) {
+                fail("node name bytes still exceeded 28 bytes limit, number of bytes is " + numberOfBytes);
+            }
+        }
+        //        for (int i = 1; i < 20000; i++) {
+        for (int i = 1; i < 2000; i++) {
+            byte[] data = new byte[i];
+            NarayanaJtaRecorder r = new NarayanaJtaRecorder();
+            transactions.nodeName = new String(data);
+            r.setNodeName(transactions);
+            int numberOfBytes = transactions.nodeName.getBytes(StandardCharsets.UTF_8).length;
+            if (numberOfBytes > 28) {
+                fail("node name bytes still exceeded 28 bytes limit, number of bytes is " + numberOfBytes);
+            }
+        }
+    }
+
+    //commented because it is a stress test
+    //    @Test
+    void testCollision() {
+        SortedSet<String> set = new TreeSet<>();
+        TransactionManagerConfiguration transactions = new TransactionManagerConfiguration();
+        transactions.shortenNodeNameIfNecessary = true;
+        // create a nodeName larger than 28 bytes
+        for (int i = 1; i < 1000000; i++) {
+            String originalNodeName = UUID.randomUUID().toString();
+            NarayanaJtaRecorder r = new NarayanaJtaRecorder();
+            transactions.nodeName = originalNodeName;
+            r.setNodeName(transactions);
+            if (set.contains(transactions.nodeName)) {
+                fail("Collision of IDs for " + transactions.nodeName);
+            }
+            set.add(transactions.nodeName);
+        }
+    }
+
+}