diff --git a/test/bin_stream_test.cpp b/test/bin_stream_test.cpp
new file mode 100644
index 0000000..209c778
--- /dev/null
+++ b/test/bin_stream_test.cpp
@@ -0,0 +1,71 @@
+#include <util/bin_stream.hpp>
+
+#include "gtest/gtest.h"
+
+enum RegisterId_t : uint32_t; // Defined in hei_types.hpp
+
+namespace util
+{
+
+/** @brief Extracts big-endian data to host RegisterId_t. */
+template <>
+inline BinFileReader& BinFileReader::operator>>(RegisterId_t& r)
+{
+    // A register ID is only 3 bytes, but there isn't a 3-byte integer type.
+    // So extract 3 bytes to a uint32_t and drop the unused byte.
+    uint32_t tmp = 0;
+    read(&tmp, 3);
+    r = static_cast<RegisterId_t>(be32toh(tmp) >> 8);
+    return *this;
+}
+
+/** @brief Inserts host RegisterId_t to big-endian data. */
+template <>
+inline BinFileWriter& BinFileWriter::operator<<(RegisterId_t r)
+{
+    // A register ID is only 3 bytes, but there isn't a 3-byte integer type.
+    // So extract 3 bytes to a uint32_t and drop the unused byte.
+    uint32_t tmp = htobe32(static_cast<uint32_t>(r) << 8);
+    write(&tmp, 3);
+    return *this;
+}
+
+} // namespace util
+
+TEST(BinStream, TestSet1)
+{
+    uint8_t w1      = 0x11;
+    uint16_t w2     = 0x1122;
+    uint32_t w3     = 0x11223344;
+    uint64_t w4     = 0x1122334455667788;
+    RegisterId_t w5 = static_cast<RegisterId_t>(0x123456);
+
+    {
+        // need scope so the writer is closed before the reader opens
+        util::BinFileWriter w{"bin_stream_test.bin"};
+        ASSERT_TRUE(w.good());
+
+        w << w1 << w2 << w3 << w4 << w5;
+        ASSERT_TRUE(w.good());
+    }
+
+    uint8_t r1;
+    uint16_t r2;
+    uint32_t r3;
+    uint64_t r4;
+    RegisterId_t r5;
+
+    {
+        util::BinFileReader r{"bin_stream_test.bin"};
+        ASSERT_TRUE(r.good());
+
+        r >> r1 >> r2 >> r3 >> r4 >> r5;
+        ASSERT_TRUE(r.good());
+    }
+
+    ASSERT_EQ(w1, r1);
+    ASSERT_EQ(w2, r2);
+    ASSERT_EQ(w3, r3);
+    ASSERT_EQ(w4, r4);
+    ASSERT_EQ(w5, r5);
+}