diff --git a/boot/modules/acquiring/src/test/java/com/klaro/acquirecore/acquiring/service/TxServiceTest.java b/boot/modules/acquiring/src/test/java/com/klaro/acquirecore/acquiring/service/TxServiceTest.java
new file mode 100644
index 0000000..d472ca1
--- /dev/null
+++ b/boot/modules/acquiring/src/test/java/com/klaro/acquirecore/acquiring/service/TxServiceTest.java
@@ -0,0 +1,94 @@
+package com.klaro.acquirecore.acquiring.service;
+
+import com.klaro.acquirecore.acquiring.codec.MessageCodec;
+import com.klaro.acquirecore.acquiring.codec.UnpackedMessage;
+import com.klaro.acquirecore.acquiring.dto.TxRequest;
+import com.klaro.acquirecore.acquiring.dto.TxResponse;
+import com.klaro.acquirecore.acquiring.repository.TxRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class TxServiceTest {
+
+    @Mock
+    private TxRepository txRepository;
+
+    private MessageCodec messageCodec;
+    private TxService txService;
+
+    @BeforeEach
+    void setUp() {
+        messageCodec = new MessageCodec();
+        txService = new TxService(messageCodec, txRepository);
+    }
+
+    @Test
+    void processMessage_validMessage_returnsApproved() {
+        String rawMessage = "0100TRX123456789MER00000012345  41111111111111112025/1230N               ";
+        TxResponse response = txService.processMessage(rawMessage.getBytes());
+
+        assertNotNull(response);
+        assertEquals("00", response.getRespCode());
+        assertEquals("Approved", response.getRespMsg());
+        verify(txRepository, times(1)).save(any(TxRequest.class));
+    }
+
+    @Test
+    void processMessage_emptyMessage_returnsError() {
+        TxResponse response = txService.processMessage(new byte[0]);
+
+        assertNotNull(response);
+        assertEquals("99", response.getRespCode());
+    }
+
+    @Test
+    void processMessage_nullMessage_returnsError() {
+        TxResponse response = txService.processMessage(null);
+
+        assertNotNull(response);
+        assertEquals("99", response.getRespCode());
+    }
+
+    @Test
+    void codec_unpackValidMessage_parsesFields() {
+        String raw = "0100TRX123456789MER00000012345  41111111111111112025/1230N               ";
+        UnpackedMessage unpacked = messageCodec.unpack(raw.getBytes());
+
+        assertEquals("0100", unpacked.getTxType());
+        assertEquals("TRX123456789", unpacked.getTraceNo());
+        assertEquals("MER00000012345", unpacked.getMerchantId());
+        assertEquals("4111111111111111", unpacked.getCardNo());
+    }
+
+    @Test
+    void codec_unpackEmpty_throwsException() {
+        assertThrows(IllegalArgumentException.class, () -> messageCodec.unpack(new byte[0]));
+    }
+
+    @Test
+    void codec_packUnpacked_roundTrips() {
+        UnpackedMessage original = new UnpackedMessage();
+        original.setTxType("0100");
+        original.setTraceNo("TRX123456789");
+        original.setMerchantId("MER00000012345");
+        original.setAmount("000000100000");
+        original.setCardNo("4111111111111111");
+        original.setExpiryDate("2025/1230");
+        original.setInstallments("00");
+        original.setFiller("");
+
+        byte[] packed = messageCodec.pack(original);
+        UnpackedMessage result = messageCodec.unpack(packed);
+
+        assertEquals(original.getTxType(), result.getTxType());
+        assertEquals(original.getTraceNo(), result.getTraceNo());
+    }
+}