diff --git a/test/file_handler_unittest.cpp b/test/file_handler_unittest.cpp
new file mode 100644
index 0000000..26a490d
--- /dev/null
+++ b/test/file_handler_unittest.cpp
@@ -0,0 +1,58 @@
+#include "file_handler.hpp"
+
+#include <cstdint>
+#include <cstdio>
+#include <fstream>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+namespace blobs
+{
+
+static constexpr auto TESTPATH = "test.output";
+
+class FileHandlerOpenTest : public ::testing::Test
+{
+  protected:
+    void TearDown() override
+    {
+        (void)std::remove(TESTPATH);
+    }
+};
+
+TEST_F(FileHandlerOpenTest, VerifyItIsHappy)
+{
+    /* Opening a fail may create it? */
+
+    FileHandler handler(TESTPATH);
+    EXPECT_TRUE(handler.open(""));
+
+    /* Calling open twice fails the second time. */
+    EXPECT_FALSE(handler.open(""));
+}
+
+TEST_F(FileHandlerOpenTest, VerifyWriteDataWrites)
+{
+    /* Verify writing bytes writes them... flushing data can be an issue here,
+     * so we close first.
+     */
+    FileHandler handler(TESTPATH);
+    EXPECT_TRUE(handler.open(""));
+
+    std::vector<std::uint8_t> bytes = {0x01, 0x02};
+    std::uint32_t offset = 0;
+
+    EXPECT_TRUE(handler.write(offset, bytes));
+    handler.close();
+
+    std::ifstream data;
+    data.open(TESTPATH, std::ios::binary);
+    char expectedBytes[2];
+    data.read(&expectedBytes[0], sizeof(expectedBytes));
+    EXPECT_EQ(expectedBytes[0], bytes[0]);
+    EXPECT_EQ(expectedBytes[1], bytes[1]);
+    /* annoyingly the memcmp was failing... but it's the same data. */
+}
+
+} // namespace blobs