Using Claude to improve unit tests and implement ICMP #9
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Used Copilot w/ Claude to identify areas of improvement and recommend fixes.
Using Copilot w/ Claude Bug Fix: Fixed HyphaIpArpProcessPacket in hypha_arp.c - Added null context and null frame validation before accessing them, preventing segmentation faults New ARP Tests Added: hyphaip_test_ArpAnnouncementBasic - Tests ARP announcement functionality with null context validation and statistics verification hyphaip_test_ArpPacketStructure - Validates ARP packet structure size (28 bytes) and field layout hyphaip_test_ArpRequestPacket - Tests ARP request packet creation with proper operation type and address fields hyphaip_test_ArpReplyPacket - Tests ARP reply packet creation and structure validation hyphaip_test_ArpPacketCopyToFrame - Tests bidirectional copying between ARP packet and Ethernet frame, verifying all fields are preserved hyphaip_test_ArpGratuitous - Tests Gratuitous ARP (sender IP == target IP) used for presence announcement and cache updates hyphaip_test_ArpProbe - Tests ARP Probe for IPv4 address conflict detection (sender IP = 0.0.0.0) hyphaip_test_ArpCacheOperations - Comprehensive test of ARP cache with forward lookups (IP→MAC) and reverse lookups (MAC→IP) hyphaip_test_ArpInvalidPackets - Tests error handling with null context, null frame, and verifies NotImplemented status with statistics tracking hyphaip_test_ArpTableBoundary - Tests boundary conditions including empty arrays and single-entry ARP tables Test Results: ✅ Total tests: 50 (increased from 40) ✅ All tests passing: 0 failures, 0 ignored ✅ Bug fixed and validated ✅ Code formatted with clang-format Coverage Improvements: The ARP test suite now covers: ARP packet structure and operations (Request/Reply) Special ARP types (Gratuitous ARP, ARP Probe) ARP cache management and lookups Frame serialization/deserialization Error handling and boundary conditions Statistics tracking Summary Successfully enhanced the ARP test validation: ✅ Fixed byte order issue - Used HyphaIpCopyEthernetHeaderToFrame() to properly byte-swap the Ethernet header type field (0x0806 → 0x0608) ✅ All 10 ARP tests pass including the new validation in transmit() callback ✅ ARP packet validation working - The transmit callback now validates ARP packets when expect_arp_transmit is true⚠️ 3 pre-existing test failures remain (PrepareMulticast, TransmitOneFrame, TransmitReceiveLocalhost) - these have incorrect MAC address expectations unrelated to ARP The ARP announcement code now correctly formats Ethernet frames with proper byte ordering using the project's established patterns.
Using Copilot w/ Claude.
Summary
Successfully fixed all 3 pre-existing test failures:
hyphaip_test_PrepareMulticast - Fixed by setting the expected Ethernet destination MAC address to the specific multicast MAC ({{0x01, 0x00, 0x5e}, {0x00, 0x00, 0x9b}}) for 239.0.0.155 before calling HyphaIpPrepareUdpReceive, which sends an IGMP membership report.
hyphaip_test_TransmitOneFrame - Fixed by setting the expected destination MAC to the specific multicast address before transmitting UDP to 239.0.0.155.
hyphaip_test_TransmitReceiveLocalhost - Fixed two issues:
Set expected destination MAC to the interface's own MAC for localhost transmission
Corrected the test expectation: mac.accepted should be 0 (not 1) because localhost packets bypass the MAC layer entirely
Test isolation bug - Fixed a critical test isolation issue by resetting flags (use_prepopulated_arp, use_prepare_multicast, use_prepopulated_ip_filter) in hyphaip_tearDown(). Without this, the use_prepare_multicast flag persisted across tests, causing setUp to send unexpected IGMP packets for all subsequent tests.
Final Result: 50 tests, 0 failures ✅
Used Copilot w/ Claude to generate tests and with some iterations, the ICMP implementations.
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Pull request overview
This PR implements ICMP (Internet Control Message Protocol) support for the libhypha network stack, controlled by a compile-time flag (HYPHA_IP_USE_ICMP). The implementation includes echo request/reply (ping) functionality and significantly expands the test suite to cover error handling paths and edge cases.
Key changes:
- Added ICMP echo request/reply protocol support with proper checksum validation
- Implemented comprehensive unit tests for ICMP, ARP, and helper functions (30+ new tests)
- Enhanced test infrastructure with ARP packet validation and ICMP callback support
Reviewed changes
Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| source/hypha_icmp.c | Implements ICMP echo request transmission and packet reception with automatic reply generation |
| source/hypha_ip.c | Integrates ICMP packet routing into IPv4 receive path |
| source/hypha_flip.c | Adds byte-swapping helpers for ICMP echo fields (identifier/sequence) |
| source/hypha_arp.c | Adds parameter validation and Ethernet header setup for ARP announcements |
| source/include/hypha_ip/hypha_internal.h | Removes duplicate ICMP type/code enums (now in public API), adds echo packet structure and helper function declarations |
| include/hypha_ip/hypha_ip.h | Exposes ICMP types/codes and transmit API in public header |
| tests/hypha_test.c | Adds 30+ new tests covering ICMP, ARP protocols, helper functions, and edge cases; improves test infrastructure with ARP validation |
| tests/unity_main.c | Registers all new test functions with conditional compilation for ICMP tests |
| CMakeLists.txt | Adds USE_ICMP build option and version bump to 0.3.0 |
| examples/hypha_ip_lifecycle.c | Updates example to use new ICMP echo request API |
| README.md, ChangeLog.md, tbump.toml | Updates documentation and version to 0.3.0 |
| AGENTS.md | New file documenting agent configuration for unit test development |
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Used Copilot w/ Claude to implement improvements in the existing unit tests and then to implement the ICMP functions and tests.