diff --git a/src/test/kotlin/com/frankenergie/smartasset/controller/OrderUpdateControllerTest.kt b/src/test/kotlin/com/frankenergie/smartasset/controller/OrderUpdateControllerTest.kt
new file mode 100644
index 0000000..2baefae
--- /dev/null
+++ b/src/test/kotlin/com/frankenergie/smartasset/controller/OrderUpdateControllerTest.kt
@@ -0,0 +1,77 @@
+package com.frankenergie.smartasset.controller
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.frankenergie.smartasset.model.OrderSide
+import com.frankenergie.smartasset.model.OrderUpdateRequest
+import org.junit.jupiter.api.Test
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.http.MediaType
+import org.springframework.test.web.servlet.MockMvc
+import org.springframework.test.web.servlet.post
+import java.math.BigDecimal
+import java.time.LocalDateTime
+
+@SpringBootTest
+@AutoConfigureMockMvc
+class OrderUpdateControllerTest {
+
+    @Autowired
+    private lateinit var mockMvc: MockMvc
+
+    @Autowired
+    private lateinit var objectMapper: ObjectMapper
+
+    @Test
+    fun `POST orderupdate returns ACCEPTED for new order`() {
+        val request = OrderUpdateRequest(
+            deliveryStartTime = LocalDateTime.of(2024, 1, 15, 10, 0),
+            deliveryEndTime = LocalDateTime.of(2024, 1, 15, 10, 15),
+            orderSide = OrderSide.BUY,
+            quantity = BigDecimal("10"),
+            price = BigDecimal("50.00")
+        )
+
+        mockMvc.post("/api/orderupdate") {
+            contentType = MediaType.APPLICATION_JSON
+            content = objectMapper.writeValueAsString(request)
+        }.andExpect {
+            status { isOk() }
+            jsonPath("$.order_id") { exists() }
+            jsonPath("$.status") { value("ACCEPTED") }
+            jsonPath("$.timestamp") { exists() }
+        }
+    }
+
+    @Test
+    fun `POST orderupdate returns FILLED when orders match`() {
+        val sellRequest = OrderUpdateRequest(
+            deliveryStartTime = LocalDateTime.of(2024, 1, 15, 11, 0),
+            deliveryEndTime = LocalDateTime.of(2024, 1, 15, 11, 15),
+            orderSide = OrderSide.SELL,
+            quantity = BigDecimal("10"),
+            price = BigDecimal("50.00")
+        )
+
+        val buyRequest = sellRequest.copy(orderSide = OrderSide.BUY)
+
+        // First, add sell order
+        mockMvc.post("/api/orderupdate") {
+            contentType = MediaType.APPLICATION_JSON
+            content = objectMapper.writeValueAsString(sellRequest)
+        }.andExpect {
+            status { isOk() }
+            jsonPath("$.status") { value("ACCEPTED") }
+        }
+
+        // Then, add matching buy order
+        mockMvc.post("/api/orderupdate") {
+            contentType = MediaType.APPLICATION_JSON
+            content = objectMapper.writeValueAsString(buyRequest)
+        }.andExpect {
+            status { isOk() }
+            jsonPath("$.status") { value("FILLED") }
+        }
+    }
+}