diff --git a/tests/modbus_server_tester.hpp b/tests/modbus_server_tester.hpp
new file mode 100644
index 0000000..79955a0
--- /dev/null
+++ b/tests/modbus_server_tester.hpp
@@ -0,0 +1,43 @@
+#pragma once
+
+#include "modbus/modbus_message.hpp"
+
+#include <sdbusplus/async.hpp>
+
+using MessageBase = phosphor::modbus::rtu::Message;
+
+namespace phosphor::modbus::test
+{
+
+class MessageIntf : public MessageBase
+{
+    friend class ServerTester;
+};
+
+static constexpr uint8_t testDeviceAddress = 0xa;
+constexpr uint16_t testSuccessReadHoldingRegisterOffset = 0x0102;
+constexpr uint16_t testSuccessReadHoldingRegisterCount = 0x2;
+constexpr uint16_t testSuccessReadHoldingRegisterSegmentedOffset = 0x0103;
+constexpr std::array<uint16_t, testSuccessReadHoldingRegisterCount>
+    testSuccessReadHoldingRegisterResponse = {0x1234, 0x5678};
+constexpr uint16_t testFailureReadHoldingRegister = 0x0105;
+
+class ServerTester
+{
+  public:
+    explicit ServerTester(sdbusplus::async::context& ctx, int fd);
+
+    auto processRequests() -> sdbusplus::async::task<void>;
+
+  private:
+    void processMessage(MessageIntf& request, size_t requestSize,
+                        MessageIntf& response, bool& segmentedResponse);
+
+    void processReadHoldingRegisters(MessageIntf& request, size_t requestSize,
+                                     MessageIntf& response,
+                                     bool& segmentedResponse);
+
+    int fd;
+    sdbusplus::async::fdio fdioInstance;
+};
+} // namespace phosphor::modbus::test