diff --git a/test/flash_unittest.cpp b/test/flash_unittest.cpp
index f4337f7..3d575df 100644
--- a/test/flash_unittest.cpp
+++ b/test/flash_unittest.cpp
@@ -15,6 +15,7 @@
 #include "commands.hpp"
 #include "flash_size.hpp"
 #include "handler_mock.hpp"
+#include "helper.hpp"
 
 #include <cstdint>
 #include <cstring>
@@ -23,8 +24,6 @@
 
 #include <gtest/gtest.h>
 
-#define MAX_IPMI_BUFFER 64
-
 using ::testing::Return;
 
 namespace google
@@ -32,34 +31,24 @@
 namespace ipmi
 {
 
-TEST(FlashSizeCommandTest, InvalidCommandLength)
-{
-    // GetFlashSizeRequest is one byte, let's send 0.
-    std::vector<std::uint8_t> request = {};
-    size_t dataLen = request.size();
-    std::uint8_t reply[MAX_IPMI_BUFFER];
-
-    HandlerMock hMock;
-    EXPECT_EQ(IPMI_CC_REQ_DATA_LEN_INVALID,
-              getFlashSize(request.data(), reply, &dataLen, &hMock));
-}
-
 TEST(FlashSizeCommandTest, ValidRequest)
 {
-    std::vector<std::uint8_t> request = {SysOEMCommands::SysGetFlashSize};
-    size_t dataLen = request.size();
-    std::uint8_t reply[MAX_IPMI_BUFFER];
+    std::vector<std::uint8_t> request = {};
     uint32_t flashSize = 5422312; // 0x52BCE8
 
     HandlerMock hMock;
     EXPECT_CALL(hMock, getFlashSize()).WillOnce(Return(flashSize));
-    EXPECT_EQ(IPMI_CC_OK,
-              getFlashSize(request.data(), reply, &dataLen, &hMock));
-    EXPECT_EQ(dataLen, 5);
-    EXPECT_EQ(reply[4], 0);
-    EXPECT_EQ(reply[3], 0x52);
-    EXPECT_EQ(reply[2], 0xBC);
-    EXPECT_EQ(reply[1], 0xE8);
+
+    auto reply = getFlashSize(request, &hMock);
+    auto result = ValidateReply(reply);
+    auto& data = result.second;
+
+    EXPECT_EQ(sizeof(struct GetFlashSizeReply), data.size());
+    EXPECT_EQ(SysOEMCommands::SysGetFlashSize, result.first);
+    EXPECT_EQ(0, data[3]);
+    EXPECT_EQ(0x52, data[2]);
+    EXPECT_EQ(0xBC, data[1]);
+    EXPECT_EQ(0xE8, data[0]);
 }
 
 } // namespace ipmi