diff --git a/tests/msgbuf.cpp b/tests/msgbuf.cpp
index 1df195e..6623fe0 100644
--- a/tests/msgbuf.cpp
+++ b/tests/msgbuf.cpp
@@ -9,16 +9,6 @@
 #define NDEBUG 1
 #endif
 
-/*
- * Fix up C11's _Static_assert() vs C++'s static_assert().
- *
- * Can we please have nice things for once.
- */
-#ifdef __cplusplus
-// NOLINTNEXTLINE(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)
-#define _Static_assert(...) static_assert(__VA_ARGS__)
-#endif
-
 #include "msgbuf.h"
 
 TEST(msgbuf, init_bad_ctx)
@@ -389,3 +379,345 @@
     EXPECT_NE(pldm_msgbuf_extract_uint8(ctx, &val[1]), PLDM_SUCCESS);
     EXPECT_EQ(pldm_msgbuf_destroy_consumed(ctx), PLDM_ERROR_INVALID_LENGTH);
 }
+
+TEST(msgbuf, pldm_msgbuf_insert_int32_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    int32_t src = -12345;
+    int32_t checkVal = 0;
+    uint8_t buf[sizeof(int32_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_int32(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_int32(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_int32_bad)
+{
+    int32_t src = -12345;
+
+    auto rc = pldm_msgbuf_insert_int32(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint32_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint32_t src = 0xf1223344;
+    uint32_t checkVal = 0;
+    uint8_t buf[sizeof(uint32_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_uint32(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint32(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint32_bad)
+{
+    uint32_t src = 0xf1223344;
+
+    auto rc = pldm_msgbuf_insert_uint32(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint16_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint16_t src = 0xf344;
+    uint16_t checkVal = 0;
+    uint8_t buf[sizeof(uint16_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(uint16_t)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_uint16(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint16(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint16_bad)
+{
+    uint16_t src = 0xf344;
+
+    auto rc = pldm_msgbuf_insert_uint16(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_int16_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    int16_t src = -12;
+    int16_t checkVal = 0;
+    uint8_t buf[sizeof(int16_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(uint16_t)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_int16(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_int16(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_int16_bad)
+{
+    int16_t src = -12;
+
+    auto rc = pldm_msgbuf_insert_int16(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint8_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src = 0xf4;
+    uint8_t checkVal = 0;
+    uint8_t buf[sizeof(uint8_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_uint8(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint8(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_uint8_bad)
+{
+    uint8_t src = 0xf4;
+
+    auto rc = pldm_msgbuf_insert_uint8(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_int8_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    int8_t src = -4;
+    int8_t checkVal = 0;
+    uint8_t buf[sizeof(int8_t)] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_int8(ctx, src), PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_int8(ctxExtract, &checkVal), PLDM_SUCCESS);
+
+    EXPECT_EQ(src, checkVal);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_int8_bad)
+{
+    int8_t src = -4;
+
+    auto rc = pldm_msgbuf_insert_int8(NULL, src);
+
+    EXPECT_EQ(rc, PLDM_ERROR_INVALID_DATA);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_array_uint8_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[6] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77};
+    uint8_t buf[6] = {};
+    uint8_t retBuff[6] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, src, sizeof(src)),
+              PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(
+        pldm_msgbuf_extract_array_uint8(ctxExtract, retBuff, sizeof(retBuff)),
+        PLDM_SUCCESS);
+
+    EXPECT_EQ(memcmp(src, retBuff, sizeof(retBuff)), 0);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_insert_array_uint8_bad)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[6] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77};
+    uint8_t buf[6] = {};
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(NULL, src, sizeof(src)),
+              PLDM_ERROR_INVALID_DATA);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, NULL, sizeof(src)),
+              PLDM_ERROR_INVALID_DATA);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_span_required_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[6] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77};
+    uint8_t buf[6] = {0};
+    const size_t required = 4;
+    uint8_t expectData[required] = {0x44, 0x55, 0x66, 0x77};
+    uint16_t testVal;
+    uint8_t* retBuff = NULL;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, src, sizeof(src)),
+              PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint16(ctxExtract, &testVal), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_span_required(ctxExtract, required, (void**)&retBuff),
+              PLDM_SUCCESS);
+
+    EXPECT_EQ(memcmp(expectData, retBuff, required), 0);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_span_required_bad)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[6] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77};
+    uint8_t buf[6] = {0};
+    const size_t required = 4;
+    uint16_t testVal;
+    [[maybe_unused]] uint8_t* retBuff = NULL;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, src, sizeof(src)),
+              PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint16(ctxExtract, &testVal), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_span_required(ctxExtract, required, NULL),
+              PLDM_ERROR_INVALID_DATA);
+    EXPECT_EQ(pldm_msgbuf_span_required(NULL, required, (void**)&retBuff),
+              PLDM_ERROR_INVALID_DATA);
+
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_span_remaining_good)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[8] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99};
+    uint8_t buf[8] = {0};
+    uint16_t testVal;
+    uint8_t expectData[6] = {0x44, 0x55, 0x66, 0x77, 0x88, 0x99};
+    size_t remaining;
+    uint8_t* retBuff = NULL;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, src, sizeof(src)),
+              PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint16(ctxExtract, &testVal), PLDM_SUCCESS);
+    EXPECT_EQ(
+        pldm_msgbuf_span_remaining(ctxExtract, (void**)&retBuff, &remaining),
+        PLDM_SUCCESS);
+
+    EXPECT_EQ(remaining, sizeof(expectData));
+    EXPECT_EQ(memcmp(expectData, retBuff, remaining), 0);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
+
+TEST(msgbuf, pldm_msgbuf_span_remaining_bad)
+{
+    struct pldm_msgbuf _ctx;
+    struct pldm_msgbuf* ctx = &_ctx;
+    uint8_t src[8] = {0x11, 0x22, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99};
+    uint8_t buf[8] = {0};
+    uint16_t testVal;
+    size_t remaining;
+    uint8_t* retBuff = NULL;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctx, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_insert_array_uint8(ctx, src, sizeof(src)),
+              PLDM_SUCCESS);
+
+    struct pldm_msgbuf _ctxExtract;
+    struct pldm_msgbuf* ctxExtract = &_ctxExtract;
+
+    ASSERT_EQ(pldm_msgbuf_init(ctxExtract, 0, buf, sizeof(buf)), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_extract_uint16(ctxExtract, &testVal), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_span_remaining(NULL, (void**)&retBuff, &remaining),
+              PLDM_ERROR_INVALID_DATA);
+    EXPECT_EQ(pldm_msgbuf_span_remaining(ctxExtract, NULL, &remaining),
+              PLDM_ERROR_INVALID_DATA);
+    EXPECT_EQ(pldm_msgbuf_span_remaining(ctxExtract, (void**)&retBuff, NULL),
+              PLDM_ERROR_INVALID_DATA);
+
+    EXPECT_EQ(pldm_msgbuf_destroy(ctxExtract), PLDM_SUCCESS);
+    EXPECT_EQ(pldm_msgbuf_destroy(ctx), PLDM_SUCCESS);
+}
\ No newline at end of file