dsp: base: Added decode_pldm_base_negotiate_transfer_params_req()

This command is based on DSP0240 v1.2.0 section 9.6.2
NegotiateTransferParameters (0x07).

gitlint-ignore: T1
Change-Id: I4fa193444df9ba5b109ca063163d7f7d109fcbda
Signed-off-by: Kasun Athukorala <kasunath@google.com>
diff --git a/tests/dsp/base.cpp b/tests/dsp/base.cpp
index 0e274a8..80edb62 100644
--- a/tests/dsp/base.cpp
+++ b/tests/dsp/base.cpp
@@ -1741,3 +1741,95 @@
     EXPECT_EQ(rc, -EOVERFLOW);
 }
 #endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(NegotiateTransferParams, TestDecodeNegotiateTransferParamsReqPass)
+{
+    // Prepare a sample request message
+    uint8_t instance_id = 0x0A;
+    uint16_t requester_part_size = 1024; // 0x0400
+    bitfield8_t requester_protocol_support[8];
+    for (int i = 0; i < 8; ++i)
+    {
+        requester_protocol_support[i].byte = static_cast<uint8_t>(i + 1);
+    }
+
+    PLDM_MSG_DEFINE_P(request,
+                      PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES);
+
+    // Build the request using the an appropriate API
+    struct pldm_base_negotiate_transfer_params_req req;
+    req.requester_part_size = requester_part_size;
+    memcpy(req.requester_protocol_support, requester_protocol_support,
+           sizeof(requester_protocol_support));
+
+    size_t req_payload_len = PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES;
+    ASSERT_EQ(encode_pldm_base_negotiate_transfer_params_req(
+                  instance_id, &req, request, &req_payload_len),
+              0);
+
+    struct pldm_base_negotiate_transfer_params_req decoded_req;
+    size_t payload_len = PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES;
+
+    // Successful decode
+    int rc = decode_pldm_base_negotiate_transfer_params_req(
+        request, payload_len, &decoded_req);
+    ASSERT_EQ(rc, 0);
+    EXPECT_EQ(decoded_req.requester_part_size, requester_part_size);
+    for (int i = 0; i < 8; ++i)
+    {
+        EXPECT_EQ(decoded_req.requester_protocol_support[i].byte,
+                  requester_protocol_support[i].byte);
+    }
+}
+#endif
+
+#ifdef LIBPLDM_API_TESTING
+TEST(NegotiateTransferParams, TestDecodeNegotiateTransferParamsReqFail)
+{
+    // Prepare a sample request message
+    uint8_t instance_id = 0x0A;
+    uint16_t requester_part_size = 1024; // 0x0400
+    bitfield8_t requester_protocol_support[8];
+    for (int i = 0; i < 8; ++i)
+    {
+        requester_protocol_support[i].byte = static_cast<uint8_t>(i + 1);
+    }
+
+    PLDM_MSG_DEFINE_P(request,
+                      PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES);
+
+    // Build the request using the an appropriate API
+    struct pldm_base_negotiate_transfer_params_req req;
+    req.requester_part_size = requester_part_size;
+    memcpy(req.requester_protocol_support, requester_protocol_support,
+           sizeof(requester_protocol_support));
+
+    size_t req_payload_len = PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES;
+    ASSERT_EQ(encode_pldm_base_negotiate_transfer_params_req(
+                  instance_id, &req, request, &req_payload_len),
+              0);
+
+    struct pldm_base_negotiate_transfer_params_req decoded_req;
+    size_t payload_len = PLDM_BASE_NEGOTIATE_TRANSFER_PARAMETERS_REQ_BYTES;
+    int rc = 0;
+
+    // Null arguments
+    rc = decode_pldm_base_negotiate_transfer_params_req(nullptr, payload_len,
+                                                        &decoded_req);
+    EXPECT_EQ(rc, -EINVAL);
+    rc = decode_pldm_base_negotiate_transfer_params_req(request, payload_len,
+                                                        nullptr);
+    EXPECT_EQ(rc, -EINVAL);
+
+    // Incorrect payload length - too short
+    rc = decode_pldm_base_negotiate_transfer_params_req(
+        request, payload_len - 1, &decoded_req);
+    EXPECT_EQ(rc, -EOVERFLOW);
+
+    // Incorrect payload length - too long
+    rc = decode_pldm_base_negotiate_transfer_params_req(
+        request, payload_len + 1, &decoded_req);
+    EXPECT_EQ(rc, -EBADMSG);
+}
+#endif