diff --git a/services/payments/src/test/java/com/klaro/bais/payments/PaymentReferenceServiceTest.java b/services/payments/src/test/java/com/klaro/bais/payments/PaymentReferenceServiceTest.java
new file mode 100644
index 0000000..83e55ad
--- /dev/null
+++ b/services/payments/src/test/java/com/klaro/bais/payments/PaymentReferenceServiceTest.java
@@ -0,0 +1,25 @@
+package com.klaro.bais.payments;
+
+import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.*;
+
+class PaymentReferenceServiceTest {
+
+    private PaymentReferenceService paymentReferenceService = new PaymentReferenceService();
+
+    @Test
+    void testNormalizeWithNull() {
+        assertEquals("", paymentReferenceService.normalize(null));
+    }
+
+    @Test
+    void testNormalizeWithBlank() {
+        assertEquals("", paymentReferenceService.normalize("  "));
+    }
+
+    @Test
+    void testNormalizeWithValidString() {
+        String input = "  test  ";
+        assertEquals("test", paymentReferenceService.normalize(input));
+    }
+}
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