diff --git a/test/flash_hashfinish_unittest.cpp b/test/flash_hashfinish_unittest.cpp
new file mode 100644
index 0000000..de785ae
--- /dev/null
+++ b/test/flash_hashfinish_unittest.cpp
@@ -0,0 +1,77 @@
+#include "flash-ipmi.hpp"
+
+#include <cstdio>
+#include <cstring>
+#include <gtest/gtest.h>
+#include <string>
+#include <vector>
+
+#define THIRTYTWO_MIB 33554432
+
+class FlashIpmiHashDataTest : public ::testing::Test
+{
+  protected:
+    FlashIpmiHashDataTest() = default;
+
+    void SetUp() override
+    {
+        name = std::tmpnam(nullptr);
+        name2 = std::tmpnam(nullptr);
+    }
+    void TearDown() override
+    {
+        (void)std::remove(name.c_str());
+        (void)std::remove(name2.c_str());
+    }
+
+    std::string name;
+    std::string name2;
+};
+
+TEST_F(FlashIpmiHashDataTest, CalledOutOfSequenceFails)
+{
+    // Verify that there is sanity checking
+    std::vector<uint8_t> bytes = {0xaa, 0x55};
+
+    FlashUpdate updater(name, name2);
+    EXPECT_FALSE(updater.hashFinish());
+
+    // Verify the file doesn't exist.
+    auto file = std::fopen(name2.c_str(), "r");
+    EXPECT_FALSE(file);
+}
+
+TEST_F(FlashIpmiHashDataTest, CalledInSequenceSucceeds)
+{
+    // Verify that under normal usage it closes the file.
+    std::vector<uint8_t> bytes = {0xaa, 0x55};
+
+    FlashUpdate updater(name, name2);
+    EXPECT_TRUE(updater.start(THIRTYTWO_MIB));
+    EXPECT_TRUE(updater.startHash(THIRTYTWO_MIB));
+    EXPECT_TRUE(updater.hashFinish());
+
+    // Verify we can open the file, so we know it didn't get deleted.
+    auto file = std::fopen(name2.c_str(), "r");
+    EXPECT_TRUE(file);
+    std::fclose(file);
+}
+
+TEST_F(FlashIpmiHashDataTest, CalledTwiceFails)
+{
+    // Verify that under normal usage it closes the file, and therefore cannot
+    // be closed twice.
+    std::vector<uint8_t> bytes = {0xaa, 0x55};
+
+    FlashUpdate updater(name, name2);
+    EXPECT_TRUE(updater.start(THIRTYTWO_MIB));
+    EXPECT_TRUE(updater.startHash(THIRTYTWO_MIB));
+    EXPECT_TRUE(updater.hashFinish());
+
+    EXPECT_FALSE(updater.hashFinish());
+
+    // Verify we can open the file, so we know it didn't get deleted.
+    auto file = std::fopen(name2.c_str(), "r");
+    EXPECT_TRUE(file);
+    std::fclose(file);
+}