diff --git a/.gitignore b/.gitignore
index b06d404c..1cf93b16 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 # Build directories
 build/
+build_asan/
 build-debug/
 build-sanitize/
 bin/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f55bba09..7d308863 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,8 +25,9 @@ endif()
 
 # Options
 option(BUILD_SHARED_LIBS "Build shared libraries" OFF)
-option(WOWEE_BUILD_TESTS "Build tests" OFF)
+option(WOWEE_BUILD_TESTS "Build tests" ON)
 option(WOWEE_ENABLE_ASAN "Enable AddressSanitizer (Debug builds)" OFF)
+option(WOWEE_ENABLE_TRACY "Enable Tracy profiler instrumentation" OFF)
 option(WOWEE_ENABLE_AMD_FSR2 "Enable AMD FidelityFX FSR2 backend when SDK is present" ON)
 option(WOWEE_ENABLE_AMD_FSR3_FRAMEGEN "Enable AMD FidelityFX SDK FSR3 frame generation interface probe when SDK is present" ON)
 option(WOWEE_BUILD_AMD_FSR3_RUNTIME "Build native AMD FidelityFX VK runtime (Path A) from extern/FidelityFX-SDK/Kits" ON)
@@ -788,6 +789,15 @@ endif()
 
 # Create executable
 add_executable(wowee ${WOWEE_SOURCES} ${WOWEE_HEADERS} ${WOWEE_PLATFORM_SOURCES})
+
+# Tracy profiler — zero overhead when WOWEE_ENABLE_TRACY is OFF
+if(WOWEE_ENABLE_TRACY)
+    target_sources(wowee PRIVATE ${CMAKE_SOURCE_DIR}/extern/tracy/public/TracyClient.cpp)
+    target_compile_definitions(wowee PRIVATE TRACY_ENABLE)
+    target_include_directories(wowee SYSTEM PRIVATE ${CMAKE_SOURCE_DIR}/extern/tracy/public)
+    message(STATUS "Tracy profiler: ENABLED")
+endif()
+
 if(TARGET opcodes-generate)
     add_dependencies(wowee opcodes-generate)
 endif()
@@ -931,6 +941,12 @@ else()
     )
 endif()
 
+# ── Unit tests (Catch2) ──────────────────────────────────────
+if(WOWEE_BUILD_TESTS)
+    enable_testing()
+    add_subdirectory(tests)
+endif()
+
 # AddressSanitizer — catch buffer overflows, use-after-free, etc.
 # Enable with:  cmake ... -DWOWEE_ENABLE_ASAN=ON -DCMAKE_BUILD_TYPE=Debug
 if(WOWEE_ENABLE_ASAN)
@@ -942,10 +958,10 @@ if(WOWEE_ENABLE_ASAN)
             $<$<CONFIG:Release>:/MD>
         )
     else()
-        target_compile_options(wowee PRIVATE -fsanitize=address -fno-omit-frame-pointer)
-        target_link_options(wowee PRIVATE -fsanitize=address)
+        target_compile_options(wowee PRIVATE -fsanitize=address,undefined -fno-omit-frame-pointer)
+        target_link_options(wowee PRIVATE -fsanitize=address,undefined)
     endif()
-    message(STATUS "AddressSanitizer: ENABLED")
+    message(STATUS "AddressSanitizer + UBSan: ENABLED")
 endif()
 
 # Release build optimizations
diff --git a/TESTING.md b/TESTING.md
new file mode 100644
index 00000000..3846b15d
--- /dev/null
+++ b/TESTING.md
@@ -0,0 +1,390 @@
+# WoWee Testing Guide
+
+This document covers everything needed to build, run, lint, and extend the WoWee test suite.
+
+---
+
+## Table of Contents
+
+1. [Overview](#overview)
+2. [Prerequisites](#prerequisites)
+3. [Test Suite Layout](#test-suite-layout)
+4. [Building the Tests](#building-the-tests)
+   - [Release Build (normal)](#release-build-normal)
+   - [Debug + ASAN/UBSan Build](#debug--asanubsan-build)
+5. [Running Tests](#running-tests)
+   - [test.sh — the unified entry point](#testsh--the-unified-entry-point)
+   - [Running directly with ctest](#running-directly-with-ctest)
+6. [Lint (clang-tidy)](#lint-clang-tidy)
+   - [Running lint](#running-lint)
+   - [Applying auto-fixes](#applying-auto-fixes)
+   - [Configuration (.clang-tidy)](#configuration-clang-tidy)
+7. [ASAN / UBSan](#asan--ubsan)
+8. [Adding New Tests](#adding-new-tests)
+9. [CI Reference](#ci-reference)
+
+---
+
+## Overview
+
+WoWee uses **Catch2 v3** (amalgamated) for unit testing and **clang-tidy** for static analysis. The `test.sh` script is the single entry point for both.
+
+| Command | What it does |
+|---|---|
+| `./test.sh` | Runs both unit tests (Release) and lint |
+| `./test.sh --test` | Runs unit tests only (Release build) |
+| `./test.sh --lint` | Runs clang-tidy only |
+| `./test.sh --asan` | Runs unit tests under ASAN + UBSan (Debug build) |
+| `FIX=1 ./test.sh --lint` | Applies clang-tidy auto-fixes in-place |
+
+All commands exit non-zero on any failure.
+
+---
+
+## Prerequisites
+
+The test suite requires the same base toolchain used to build the project. See [BUILD_INSTRUCTIONS.md](BUILD_INSTRUCTIONS.md) for platform-specific dependency installation.
+
+### Linux (Ubuntu / Debian)
+
+```bash
+sudo apt update
+sudo apt install -y \
+  build-essential cmake pkg-config git \
+  libssl-dev \
+  clang-tidy
+```
+
+### Linux (Arch)
+
+```bash
+sudo pacman -S --needed base-devel cmake pkgconf git openssl clang
+```
+
+### macOS
+
+```bash
+brew install cmake openssl@3 llvm
+# Add LLVM tools to PATH so clang-tidy is found:
+export PATH="$(brew --prefix llvm)/bin:$PATH"
+```
+
+### Windows (MSYS2)
+
+Install the full toolchain as described in `BUILD_INSTRUCTIONS.md`, then add:
+
+```bash
+pacman -S --needed mingw-w64-x86_64-clang-tools-extra
+```
+
+---
+
+## Test Suite Layout
+
+```
+tests/
+  CMakeLists.txt         — CMake test configuration
+  test_packet.cpp        — Network packet encode/decode
+  test_srp.cpp           — SRP-6a authentication math (requires OpenSSL)
+  test_opcode_table.cpp  — Opcode registry lookup
+  test_entity.cpp        — ECS entity basics
+  test_dbc_loader.cpp    — DBC binary file parsing
+  test_m2_structs.cpp    — M2 model struct layout / alignment
+  test_blp_loader.cpp    — BLP texture file parsing
+  test_frustum.cpp       — View-frustum culling math
+```
+
+The Catch2 v3 amalgamated source lives at:
+
+```
+extern/catch2/
+  catch_amalgamated.hpp
+  catch_amalgamated.cpp
+```
+
+---
+
+## Building the Tests
+
+Tests are _not_ built by default. Enable them with `-DWOWEE_BUILD_TESTS=ON`.
+
+### Release Build (normal)
+
+> **Note:** Per project rules, always use `rebuild.sh` for a full clean build. Direct `cmake --build` is fine for test-only incremental builds.
+
+```bash
+# Configure (only needed once)
+cmake -B build -DCMAKE_BUILD_TYPE=Release -DWOWEE_BUILD_TESTS=ON
+
+# Build test targets (fast — only compiles tests and Catch2)
+cmake --build build --target \
+  test_packet test_srp test_opcode_table test_entity \
+  test_dbc_loader test_m2_structs test_blp_loader test_frustum
+```
+
+Or simply run a full rebuild (builds everything including the main binary):
+
+```bash
+./rebuild.sh      # ~10 minutes — see BUILD_INSTRUCTIONS.md
+```
+
+### Debug + ASAN/UBSan Build
+
+A separate CMake build directory is used so ASAN flags do not pollute the Release binary.
+
+```bash
+cmake -B build_asan \
+  -DCMAKE_BUILD_TYPE=Debug \
+  -DWOWEE_ENABLE_ASAN=ON \
+  -DWOWEE_BUILD_TESTS=ON
+
+cmake --build build_asan --target \
+  test_packet test_srp test_opcode_table test_entity \
+  test_dbc_loader test_m2_structs test_blp_loader test_frustum
+```
+
+CMake will print: `Test targets: ASAN + UBSan ENABLED` when configured correctly.
+
+---
+
+## Running Tests
+
+### test.sh — the unified entry point
+
+`test.sh` is the recommended way to run tests and/or lint. It handles build-directory discovery, dependency checking, and exit-code aggregation across both steps.
+
+```bash
+# Run everything (tests + lint) — default when no flags are given
+./test.sh
+
+# Tests only (Release build)
+./test.sh --test
+
+# Tests only under ASAN+UBSan (Debug build — requires build_asan/)
+./test.sh --asan
+
+# Lint only
+./test.sh --lint
+
+# Both tests and lint explicitly
+./test.sh --test --lint
+
+# Usage summary
+./test.sh --help
+```
+
+**Exit codes:**
+
+| Outcome | Exit code |
+|---|---|
+| All tests passed, lint clean | `0` |
+| Any test failed | `1` |
+| Any lint diagnostic | `1` |
+| Both test failure and lint issues | `1` |
+
+### Running directly with ctest
+
+```bash
+# Release build
+cd build
+ctest --output-on-failure
+
+# ASAN build
+cd build_asan
+ctest --output-on-failure
+
+# Run one specific test suite by name
+ctest --output-on-failure -R srp
+
+# Verbose output (shows every SECTION and REQUIRE)
+ctest --output-on-failure -V
+```
+
+You can also run a test binary directly for detailed Catch2 output:
+
+```bash
+./build/bin/test_srp
+./build/bin/test_srp --reporter console
+./build/bin/test_srp "[authentication]"    # run only tests tagged [authentication]
+```
+
+---
+
+## Lint (clang-tidy)
+
+The project uses clang-tidy to enforce C++20 best practices on all first-party sources under `src/`. Third-party code (anything in `extern/`) and generated files are excluded.
+
+### Running lint
+
+```bash
+./test.sh --lint
+```
+
+Under the hood the script:
+
+1. Locates `clang-tidy` (tries versions 14–18, then `clang-tidy`).
+2. Uses `run-clang-tidy` for parallel execution when available; falls back to sequential.
+3. Reads `build/compile_commands.json` (generated by CMake) for compiler flags.
+4. Feeds GCC stdlib include paths as `-isystem` extras so clang-tidy can resolve `<vector>`, `<string>`, etc. when the compile-commands were generated with GCC.
+
+`compile_commands.json` is regenerated automatically by any CMake configure step. If you only want to update it without rebuilding:
+
+```bash
+cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+```
+
+### Applying auto-fixes
+
+Some clang-tidy checks can apply fixes automatically (e.g. `modernize-*`, `readability-*`):
+
+```bash
+FIX=1 ./test.sh --lint
+```
+
+> **Caution:** Review the diff before committing — automatic fixes occasionally produce non-idiomatic results in complex template code.
+
+### Configuration (.clang-tidy)
+
+The active check set is defined in [.clang-tidy](.clang-tidy) at the repository root.
+
+**Enabled check categories:**
+
+| Category | What it catches |
+|---|---|
+| `bugprone-*` | Common bug patterns (signed overflow, misplaced `=`, etc.) |
+| `clang-analyzer-*` | Deep flow-analysis: null dereferences, memory leaks, dead stores |
+| `performance-*` | Unnecessary copies, inefficient STL usage |
+| `modernize-*` (subset) | Pre-C++11 patterns that should use modern equivalents |
+| `readability-*` (subset) | Control-flow simplification, redundant code |
+
+**Notable suppressions** (see `.clang-tidy` for details):
+
+| Suppressed check | Reason |
+|---|---|
+| `bugprone-easily-swappable-parameters` | High false-positive rate in graphics/math APIs |
+| `clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling` | Intentional low-level buffer code in rendering |
+| `performance-avoid-endl` | `std::endl` is used intentionally for logger flushing |
+
+To suppress a specific warning inline, use:
+
+```cpp
+// NOLINT(bugprone-narrowing-conversions)
+uint8_t byte = static_cast<uint8_t>(value); // NOLINT
+```
+
+---
+
+## ASAN / UBSan
+
+AddressSanitizer (ASAN) and Undefined Behaviour Sanitizer (UBSan) are applied to all test targets when `WOWEE_ENABLE_ASAN=ON`.
+
+Both the test executables **and** the `catch2_main` static library are recompiled with:
+
+```
+-fsanitize=address,undefined -fno-omit-frame-pointer
+```
+
+This means any heap overflow, stack buffer overflow, use-after-free, null dereference, signed integer overflow, or misaligned access detected during a test will abort the process and print a human-readable report to stderr.
+
+### Workflow
+
+```bash
+# 1. Configure once (only needs to be re-run when CMakeLists.txt changes)
+cmake -B build_asan \
+  -DCMAKE_BUILD_TYPE=Debug \
+  -DWOWEE_ENABLE_ASAN=ON \
+  -DWOWEE_BUILD_TESTS=ON
+
+# 2. Build test binaries (fast incremental after the first build)
+cmake --build build_asan --target test_packet test_srp   # etc.
+
+# 3. Run
+./test.sh --asan
+```
+
+### Interpreting ASAN output
+
+A failing ASAN report looks like:
+
+```
+==12345==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000010
+READ of size 4 at 0x602000000010 thread T0
+    #0 0x... in PacketBuffer::read_uint32 src/network/packet.cpp:42
+    #1 0x... in test_packet tests/test_packet.cpp:88
+```
+
+Address the issue in the source file and re-run. Do **not** suppress ASAN reports without a code fix.
+
+---
+
+## Adding New Tests
+
+1. **Create** `tests/test_<name>.cpp` with a standard Catch2 v3 structure:
+
+```cpp
+#include "catch_amalgamated.hpp"
+
+TEST_CASE("SomeFeature does X", "[tag]") {
+    REQUIRE(1 + 1 == 2);
+}
+```
+
+2. **Register** the test in `tests/CMakeLists.txt` following the existing pattern:
+
+```cmake
+# ── test_<name> ──────────────────────────────────────────────
+add_executable(test_<name>
+    test_<name>.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/<module>/<file>.cpp   # source under test
+)
+target_include_directories(test_<name> PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_<name> SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_<name> PRIVATE catch2_main)
+add_test(NAME <name> COMMAND test_<name>)
+register_test_target(test_<name>)   # required — enables ASAN propagation
+```
+
+3. **Build** and verify:
+
+```bash
+cmake --build build --target test_<name>
+./test.sh --test
+```
+
+The `register_test_target()` macro call is **mandatory** — without it the new test will not receive ASAN/UBSan flags when `WOWEE_ENABLE_ASAN=ON`.
+
+---
+
+## CI Reference
+
+The following commands map to typical CI jobs:
+
+| Job | Command |
+|---|---|
+| Unit tests (Release) | `./test.sh --test` |
+| Unit tests (ASAN+UBSan) | `./test.sh --asan` |
+| Lint | `./test.sh --lint` |
+| Full check (tests + lint) | `./test.sh` |
+
+**Configuring the ASAN job in CI:**
+
+```yaml
+- name: Configure ASAN build
+  run: |
+    cmake -B build_asan \
+      -DCMAKE_BUILD_TYPE=Debug \
+      -DWOWEE_ENABLE_ASAN=ON \
+      -DWOWEE_BUILD_TESTS=ON
+
+- name: Build test targets
+  run: |
+    cmake --build build_asan --target \
+      test_packet test_srp test_opcode_table test_entity \
+      test_dbc_loader test_m2_structs test_blp_loader test_frustum
+
+- name: Run ASAN tests
+  run: ./test.sh --asan
+```
+
+> See [BUILD_INSTRUCTIONS.md](BUILD_INSTRUCTIONS.md) for full platform dependency installation steps required before any CI job.
diff --git a/docs/perf_baseline.md b/docs/perf_baseline.md
new file mode 100644
index 00000000..88bdc743
--- /dev/null
+++ b/docs/perf_baseline.md
@@ -0,0 +1,79 @@
+# Performance Baseline — WoWee
+
+> Phase 0.3 deliverable. Measurements taken before any optimization work.
+> Re-run after each phase to quantify improvement.
+
+## Tracy Profiler Integration
+
+Tracy v0.11.1 integrated under `WOWEE_ENABLE_TRACY` CMake option (default: OFF).
+When enabled, zero-cost zone markers instrument the following critical paths:
+
+### Instrumented Zones
+
+| Zone Name | File | Purpose |
+|-----------|------|---------|
+| `Application::run` | src/core/application.cpp | Main loop entry |
+| `Application::update` | src/core/application.cpp | Per-frame game logic |
+| `Renderer::beginFrame` | src/rendering/renderer.cpp | Vulkan frame begin |
+| `Renderer::endFrame` | src/rendering/renderer.cpp | Post-process + present |
+| `Renderer::update` | src/rendering/renderer.cpp | Renderer per-frame update |
+| `Renderer::renderWorld` | src/rendering/renderer.cpp | Main world draw call |
+| `Renderer::renderShadowPass` | src/rendering/renderer.cpp | Shadow depth pass |
+| `PostProcess::execute` | src/rendering/post_process_pipeline.cpp | FSR/FXAA post-process |
+| `M2::computeBoneMatrices` | src/rendering/m2_renderer.cpp | CPU skeletal animation |
+| `M2Renderer::update` | src/rendering/m2_renderer.cpp | M2 instance update + culling |
+| `TerrainManager::update` | src/rendering/terrain_manager.cpp | Terrain streaming logic |
+| `TerrainManager::processReadyTiles` | src/rendering/terrain_manager.cpp | GPU tile uploads |
+| `ADTLoader::load` | src/pipeline/adt_loader.cpp | ADT binary parsing |
+| `AssetManager::loadTexture` | src/pipeline/asset_manager.cpp | BLP texture loading |
+| `AssetManager::loadDBC` | src/pipeline/asset_manager.cpp | DBC data file loading |
+| `WorldSocket::update` | src/network/world_socket.cpp | Network packet dispatch |
+
+`FrameMark` placed at frame boundary in Application::update to track FPS.
+
+### How to Profile
+
+```bash
+# Build with Tracy enabled
+mkdir -p build_tracy && cd build_tracy
+cmake .. -DCMAKE_BUILD_TYPE=RelWithDebInfo -DWOWEE_ENABLE_TRACY=ON
+cmake --build . --parallel $(nproc)
+
+# Run the client — Tracy will broadcast on default port (8086)
+cd bin && ./wowee
+
+# Connect with Tracy profiler GUI (separate download from https://github.com/wolfpld/tracy/releases)
+# Or capture from CLI: tracy-capture -o trace.tracy
+```
+
+## Baseline Scenarios
+
+> **TODO:** Record measurements once profiler is connected to a running instance.
+> Each scenario should record: avg FPS, frame time (p50/p95/p99), and per-zone timings.
+
+### Scenario 1: Stormwind (Heavy M2/WMO)
+- **Location:** Stormwind City center
+- **Load:** Dense M2 models (NPCs, doodads), multiple WMO interiors
+- **Avg FPS:** _pending_
+- **Frame time (p50/p95/p99):** _pending_
+- **Top zones:** _pending_
+
+### Scenario 2: The Barrens (Heavy Terrain)
+- **Location:** Central Barrens
+- **Load:** Many terrain tiles loaded, sparse M2, large draw distance
+- **Avg FPS:** _pending_
+- **Frame time (p50/p95/p99):** _pending_
+- **Top zones:** _pending_
+
+### Scenario 3: Dungeon Instance (WMO-only)
+- **Location:** Any dungeon instance (e.g., Deadmines entrance)
+- **Load:** WMO interior rendering, no terrain
+- **Avg FPS:** _pending_
+- **Frame time (p50/p95/p99):** _pending_
+- **Top zones:** _pending_
+
+## Notes
+
+- When `WOWEE_ENABLE_TRACY` is OFF (default), all `ZoneScopedN` / `FrameMark` macros expand to nothing — zero runtime overhead.
+- Tracy requires a network connection to capture traces. Run the Tracy profiler GUI or `tracy-capture` CLI alongside the client.
+- Debug builds are significantly slower due to -Og and no LTO; use RelWithDebInfo for representative measurements.
diff --git a/include/core/profiler.hpp b/include/core/profiler.hpp
new file mode 100644
index 00000000..7b1b4745
--- /dev/null
+++ b/include/core/profiler.hpp
@@ -0,0 +1,19 @@
+// Thin wrapper around Tracy profiler.
+// When TRACY_ENABLE is not defined, all macros expand to nothing (zero overhead).
+#pragma once
+
+#ifdef TRACY_ENABLE
+#include <tracy/Tracy.hpp>
+#else
+// No-op replacements when Tracy is disabled.
+#define ZoneScoped
+#define ZoneScopedN(x)
+#define ZoneScopedC(x)
+#define ZoneScopedNC(x, y)
+#define FrameMark
+#define FrameMarkNamed(x)
+#define FrameMarkStart(x)
+#define FrameMarkEnd(x)
+#define TracyPlot(x, y)
+#define TracyMessageL(x)
+#endif
diff --git a/src/core/application.cpp b/src/core/application.cpp
index 3e17ab22..1a16e5ce 100644
--- a/src/core/application.cpp
+++ b/src/core/application.cpp
@@ -1,5 +1,6 @@
 #include "core/application.hpp"
 #include "core/coordinates.hpp"
+#include "core/profiler.hpp"
 #include <unordered_set>
 #include <cmath>
 #include <chrono>
@@ -569,6 +570,7 @@ bool Application::initialize() {
 }
 
 void Application::run() {
+    ZoneScopedN("Application::run");
     LOG_INFO("Starting main loop");
 
     // Pin main thread to a dedicated CPU core to reduce scheduling jitter
@@ -759,6 +761,7 @@ void Application::run() {
 
             // Update application state
             try {
+                FrameMark;
                 update(deltaTime);
             } catch (const std::bad_alloc& e) {
                 LOG_ERROR("OOM during Application::update (state=", static_cast<int>(state),
@@ -1110,6 +1113,7 @@ void Application::logoutToLogin() {
 }
 
 void Application::update(float deltaTime) {
+    ZoneScopedN("Application::update");
     const char* updateCheckpoint = "enter";
     try {
     // Update based on current state
diff --git a/src/game/game_handler.cpp b/src/game/game_handler.cpp
index 6735d0cd..bc674daf 100644
--- a/src/game/game_handler.cpp
+++ b/src/game/game_handler.cpp
@@ -5304,40 +5304,9 @@ void GameHandler::acceptBattlefield(uint32_t queueSlot) {
 // ---------------------------------------------------------------------------
 // LFG / Dungeon Finder handlers (WotLK 3.3.5a)
 // ---------------------------------------------------------------------------
-
-static const char* lfgJoinResultString(uint8_t result) {
-    switch (result) {
-        case 0:  return nullptr; // success
-        case 1:  return "Role check failed.";
-        case 2:  return "No LFG slots available for your group.";
-        case 3:  return "No LFG object found.";
-        case 4:  return "No slots available (player).";
-        case 5:  return "No slots available (party).";
-        case 6:  return "Dungeon requirements not met by all members.";
-        case 7:  return "Party members are from different realms.";
-        case 8:  return "Not all members are present.";
-        case 9:  return "Get info timeout.";
-        case 10: return "Invalid dungeon slot.";
-        case 11: return "You are marked as a deserter.";
-        case 12: return "A party member is marked as a deserter.";
-        case 13: return "You are on a random dungeon cooldown.";
-        case 14: return "A party member is on a random dungeon cooldown.";
-        case 16: return "No spec/role available.";
-        default: return "Cannot join dungeon finder.";
-    }
-}
-
-static const char* lfgTeleportDeniedString(uint8_t reason) {
-    switch (reason) {
-        case 0:  return "You are not in a LFG group.";
-        case 1:  return "You are not in the dungeon.";
-        case 2:  return "You have a summon pending.";
-        case 3:  return "You are dead.";
-        case 4:  return "You have Deserter.";
-        case 5:  return "You do not meet the requirements.";
-        default: return "Teleport to dungeon denied.";
-    }
-}
+// NOTE: lfgJoinResultString() and lfgTeleportDeniedString() live in
+// social_handler.cpp where they are actually called.
+// ---------------------------------------------------------------------------
 
 // ---------------------------------------------------------------------------
 // LFG outgoing packets
diff --git a/src/network/world_socket.cpp b/src/network/world_socket.cpp
index ca34cf11..a3cc56b9 100644
--- a/src/network/world_socket.cpp
+++ b/src/network/world_socket.cpp
@@ -4,6 +4,7 @@
 #include "game/opcode_table.hpp"
 #include "auth/crypto.hpp"
 #include "core/logger.hpp"
+#include "core/profiler.hpp"
 #include <iomanip>
 #include <sstream>
 #include <cstdio>
@@ -464,6 +465,7 @@ void WorldSocket::send(const Packet& packet) {
 }
 
 void WorldSocket::update() {
+    ZoneScopedN("WorldSocket::update");
     if (!useAsyncPump_) {
         pumpNetworkIO();
     }
diff --git a/src/pipeline/adt_loader.cpp b/src/pipeline/adt_loader.cpp
index c629606b..12154407 100644
--- a/src/pipeline/adt_loader.cpp
+++ b/src/pipeline/adt_loader.cpp
@@ -1,5 +1,6 @@
 #include "pipeline/adt_loader.hpp"
 #include "core/logger.hpp"
+#include "core/profiler.hpp"
 #include <cstring>
 #include <cmath>
 #include <algorithm>
@@ -28,6 +29,7 @@ float HeightMap::getHeight(int x, int y) const {
 
 // ADTLoader implementation
 ADTTerrain ADTLoader::load(const std::vector<uint8_t>& adtData) {
+    ZoneScopedN("ADTLoader::load");
     ADTTerrain terrain;
 
     if (adtData.empty()) {
diff --git a/src/pipeline/asset_manager.cpp b/src/pipeline/asset_manager.cpp
index 017b0ff6..8429bb5b 100644
--- a/src/pipeline/asset_manager.cpp
+++ b/src/pipeline/asset_manager.cpp
@@ -1,6 +1,7 @@
 #include "pipeline/asset_manager.hpp"
 #include "core/logger.hpp"
 #include "core/memory_monitor.hpp"
+#include "core/profiler.hpp"
 #include <algorithm>
 #include <cstdlib>
 #include <filesystem>
@@ -166,6 +167,7 @@ void AssetManager::setBaseFallbackPath(const std::string& basePath) {
 }
 
 BLPImage AssetManager::loadTexture(const std::string& path) {
+    ZoneScopedN("AssetManager::loadTexture");
     if (!initialized) {
         LOG_ERROR("AssetManager not initialized");
         return BLPImage();
@@ -265,6 +267,7 @@ void AssetManager::setExpansionDataPath(const std::string& path) {
 }
 
 std::shared_ptr<DBCFile> AssetManager::loadDBC(const std::string& name) {
+    ZoneScopedN("AssetManager::loadDBC");
     if (!initialized) {
         LOG_ERROR("AssetManager not initialized");
         return nullptr;
diff --git a/src/rendering/m2_renderer.cpp b/src/rendering/m2_renderer.cpp
index f103e1ea..a5d8f546 100644
--- a/src/rendering/m2_renderer.cpp
+++ b/src/rendering/m2_renderer.cpp
@@ -12,6 +12,7 @@
 #include "pipeline/asset_manager.hpp"
 #include "pipeline/blp_loader.hpp"
 #include "core/logger.hpp"
+#include "core/profiler.hpp"
 #include <chrono>
 #include <cctype>
 #include <glm/gtc/matrix_transform.hpp>
@@ -1866,6 +1867,7 @@ static glm::quat interpQuat(const pipeline::M2AnimationTrack& track,
 }
 
 static void computeBoneMatrices(const M2ModelGPU& model, M2Instance& instance) {
+    ZoneScopedN("M2::computeBoneMatrices");
     size_t numBones = std::min(model.bones.size(), size_t(128));
     if (numBones == 0) return;
     instance.boneMatrices.resize(numBones);
@@ -1898,6 +1900,7 @@ static void computeBoneMatrices(const M2ModelGPU& model, M2Instance& instance) {
 }
 
 void M2Renderer::update(float deltaTime, const glm::vec3& cameraPos, const glm::mat4& viewProjection) {
+    ZoneScopedN("M2Renderer::update");
     if (spatialIndexDirty_) {
         rebuildSpatialIndex();
     }
diff --git a/src/rendering/post_process_pipeline.cpp b/src/rendering/post_process_pipeline.cpp
index fd0c49f0..c4522b9d 100644
--- a/src/rendering/post_process_pipeline.cpp
+++ b/src/rendering/post_process_pipeline.cpp
@@ -8,6 +8,7 @@
 #include "rendering/camera.hpp"
 #include "rendering/amd_fsr3_runtime.hpp"
 #include "core/logger.hpp"
+#include "core/profiler.hpp"
 #include <cstdlib>
 #include <algorithm>
 #include <glm/gtc/matrix_inverse.hpp>
@@ -152,6 +153,7 @@ bool PostProcessPipeline::hasActivePostProcess() const {
 
 bool PostProcessPipeline::executePostProcessing(VkCommandBuffer cmd, uint32_t imageIndex,
                                                   Camera* camera, float deltaTime) {
+    ZoneScopedN("PostProcess::execute");
     currentCmd_ = cmd;
     camera_ = camera;
     lastDeltaTime_ = deltaTime;
diff --git a/src/rendering/renderer.cpp b/src/rendering/renderer.cpp
index ddd39746..74ff2194 100644
--- a/src/rendering/renderer.cpp
+++ b/src/rendering/renderer.cpp
@@ -13,6 +13,7 @@
 #include "rendering/weather.hpp"
 #include "rendering/lightning.hpp"
 #include "rendering/lighting_manager.hpp"
+#include "core/profiler.hpp"
 #include "rendering/sky_system.hpp"
 #include "rendering/swim_effects.hpp"
 #include "rendering/mount_dust.hpp"
@@ -797,6 +798,7 @@ void Renderer::applyMsaaChange() {
 }
 
 void Renderer::beginFrame() {
+    ZoneScopedN("Renderer::beginFrame");
     if (!vkCtx) return;
     if (vkCtx->isDeviceLost()) return;
 
@@ -924,6 +926,7 @@ void Renderer::beginFrame() {
 }
 
 void Renderer::endFrame() {
+    ZoneScopedN("Renderer::endFrame");
     if (!vkCtx || currentCmd == VK_NULL_HANDLE) return;
 
     // Track whether a post-processing path switched to an INLINE render pass.
@@ -1190,6 +1193,7 @@ bool Renderer::isMoving() const {
 }
 
 void Renderer::update(float deltaTime) {
+    ZoneScopedN("Renderer::update");
     globalTime += deltaTime;
     if (musicSwitchCooldown_ > 0.0f) {
         musicSwitchCooldown_ = std::max(0.0f, musicSwitchCooldown_ - deltaTime);
@@ -1975,6 +1979,7 @@ float Renderer::getBrightness() const {
 }
 
 void Renderer::renderWorld(game::World* world, game::GameHandler* gameHandler) {
+    ZoneScopedN("Renderer::renderWorld");
     (void)world;
 
     // Guard against null command buffer (e.g. after VK_ERROR_DEVICE_LOST)
@@ -3042,6 +3047,7 @@ void Renderer::renderReflectionPass() {
 }
 
 void Renderer::renderShadowPass() {
+    ZoneScopedN("Renderer::renderShadowPass");
     static const bool skipShadows = (std::getenv("WOWEE_SKIP_SHADOWS") != nullptr);
     if (skipShadows) return;
     if (!shadowsEnabled || shadowDepthImage[0] == VK_NULL_HANDLE) return;
diff --git a/src/rendering/terrain_manager.cpp b/src/rendering/terrain_manager.cpp
index a0944bb0..2639a1b1 100644
--- a/src/rendering/terrain_manager.cpp
+++ b/src/rendering/terrain_manager.cpp
@@ -8,6 +8,7 @@
 #include "audio/ambient_sound_manager.hpp"
 #include "core/coordinates.hpp"
 #include "core/memory_monitor.hpp"
+#include "core/profiler.hpp"
 #include "pipeline/asset_manager.hpp"
 #include "pipeline/adt_loader.hpp"
 #include "pipeline/m2_loader.hpp"
@@ -188,6 +189,7 @@ bool TerrainManager::initialize(pipeline::AssetManager* assets, TerrainRenderer*
 }
 
 void TerrainManager::update(const Camera& camera, float deltaTime) {
+    ZoneScopedN("TerrainManager::update");
     if (!streamingEnabled || !assetManager || !terrainRenderer) {
         return;
     }
@@ -1236,6 +1238,7 @@ void TerrainManager::workerLoop() {
 }
 
 void TerrainManager::processReadyTiles() {
+    ZoneScopedN("TerrainManager::processReadyTiles");
     // Move newly ready tiles into the finalizing deque.
     // Keep them in pendingTiles so streamTiles() won't re-enqueue them.
     {
diff --git a/src/ui/game_screen.cpp b/src/ui/game_screen.cpp
index f4cbb833..779510ec 100644
--- a/src/ui/game_screen.cpp
+++ b/src/ui/game_screen.cpp
@@ -140,50 +140,8 @@ namespace {
         return "Unknown";
     }
 
-    // Collect all non-comment, non-empty lines from a macro body.
-    std::vector<std::string> allMacroCommands(const std::string& macroText) {
-        std::vector<std::string> cmds;
-        size_t pos = 0;
-        while (pos <= macroText.size()) {
-            size_t nl = macroText.find('\n', pos);
-            std::string line = (nl != std::string::npos) ? macroText.substr(pos, nl - pos) : macroText.substr(pos);
-            if (!line.empty() && line.back() == '\r') line.pop_back();
-            size_t start = line.find_first_not_of(" \t");
-            if (start != std::string::npos) line = line.substr(start);
-            if (!line.empty() && line.front() != '#')
-                cmds.push_back(std::move(line));
-            if (nl == std::string::npos) break;
-            pos = nl + 1;
-        }
-        return cmds;
-    }
-
-    // Returns the #showtooltip argument from a macro body.
-    std::string getMacroShowtooltipArg(const std::string& macroText) {
-        size_t pos = 0;
-        while (pos <= macroText.size()) {
-            size_t nl = macroText.find('\n', pos);
-            std::string line = (nl != std::string::npos) ? macroText.substr(pos, nl - pos) : macroText.substr(pos);
-            if (!line.empty() && line.back() == '\r') line.pop_back();
-            size_t fs = line.find_first_not_of(" \t");
-            if (fs != std::string::npos) line = line.substr(fs);
-            if (line.rfind("#showtooltip", 0) == 0 || line.rfind("#show", 0) == 0) {
-                size_t sp = line.find(' ');
-                if (sp != std::string::npos) {
-                    std::string arg = line.substr(sp + 1);
-                    size_t as = arg.find_first_not_of(" \t");
-                    if (as != std::string::npos) arg = arg.substr(as);
-                    size_t ae = arg.find_last_not_of(" \t");
-                    if (ae != std::string::npos) arg.resize(ae + 1);
-                    if (!arg.empty()) return arg;
-                }
-                return "__auto__";
-            }
-            if (nl == std::string::npos) break;
-            pos = nl + 1;
-        }
-        return {};
-    }
+    // NOTE: allMacroCommands() and getMacroShowtooltipArg() live in
+    // action_bar_panel.cpp / chat_panel.cpp where they are actually used.
 }
 
 namespace wowee { namespace ui {
diff --git a/test.sh b/test.sh
index 7b69156b..e8d8b536 100755
--- a/test.sh
+++ b/test.sh
@@ -1,11 +1,22 @@
 #!/usr/bin/env bash
-# test.sh — Run the C++ linter (clang-tidy) against all first-party sources.
+# test.sh — Run the Catch2 unit tests and/or clang-tidy linter.
 #
 # Usage:
-#   ./test.sh            # lint src/ and include/ using build/compile_commands.json
-#   FIX=1 ./test.sh      # apply suggested fixes automatically (use with care)
+#   ./test.sh                    # run both lint and tests (default)
+#   ./test.sh --lint             # run clang-tidy only
+#   ./test.sh --test             # run ctest unit tests only
+#   ./test.sh --lint --test      # explicit: run both
+#   ./test.sh --asan             # run ctest under ASAN/UBSan (requires build_asan/)
+#   ./test.sh --test --asan      # same as above
+#   FIX=1 ./test.sh --lint       # apply clang-tidy fix suggestions (use with care)
 #
-# Exit code is non-zero if any clang-tidy diagnostic is emitted.
+# Exit code is non-zero if any lint diagnostic or test failure is reported.
+#
+# Build directories:
+#   build/       — Release build used for normal ctest  (cmake -DCMAKE_BUILD_TYPE=Release)
+#   build_asan/  — Debug+ASAN build used with --asan    (cmake -DCMAKE_BUILD_TYPE=Debug
+#                                                              -DWOWEE_ENABLE_ASAN=ON
+#                                                              -DWOWEE_BUILD_TESTS=ON)
 
 set -euo pipefail
 
@@ -13,8 +24,88 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 cd "$SCRIPT_DIR"
 
 # ---------------------------------------------------------------------------
-# Dependency check
+# Argument parsing
 # ---------------------------------------------------------------------------
+RUN_LINT=0
+RUN_TEST=0
+RUN_ASAN=0
+
+for arg in "$@"; do
+    case "$arg" in
+        --lint) RUN_LINT=1 ;;
+        --test) RUN_TEST=1 ;;
+        --asan) RUN_ASAN=1; RUN_TEST=1 ;;
+        --help|-h)
+            sed -n '2,18p' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'
+            exit 0
+            ;;
+        *)
+            echo "Unknown argument: $arg"
+            echo "Usage: $0 [--lint] [--test] [--asan]"
+            exit 1
+            ;;
+    esac
+done
+
+# Default: run both when no flags provided
+if [[ $RUN_LINT -eq 0 && $RUN_TEST -eq 0 ]]; then
+    RUN_LINT=1
+    RUN_TEST=1
+fi
+
+# ---------------------------------------------------------------------------
+# ── UNIT TESTS ─────────────────────────────────────────────────────────────
+# ---------------------------------------------------------------------------
+OVERALL_FAILED=0
+
+if [[ $RUN_TEST -eq 1 ]]; then
+    if [[ $RUN_ASAN -eq 1 ]]; then
+        BUILD_TEST_DIR="$SCRIPT_DIR/build_asan"
+        TEST_LABEL="ASAN+UBSan"
+    else
+        BUILD_TEST_DIR="$SCRIPT_DIR/build"
+        TEST_LABEL="Release"
+    fi
+
+    if [[ ! -d "$BUILD_TEST_DIR" ]]; then
+        echo "Build directory not found: $BUILD_TEST_DIR"
+        if [[ $RUN_ASAN -eq 1 ]]; then
+            echo "Configure it with:"
+            echo "  cmake -B build_asan -DCMAKE_BUILD_TYPE=Debug -DWOWEE_ENABLE_ASAN=ON -DWOWEE_BUILD_TESTS=ON"
+        else
+            echo "Run cmake first:  cmake -B build -DCMAKE_BUILD_TYPE=Release -DWOWEE_BUILD_TESTS=ON"
+        fi
+        exit 1
+    fi
+
+    # Check that CTestTestfile.cmake exists (tests were configured)
+    if [[ ! -f "$BUILD_TEST_DIR/CTestTestfile.cmake" ]]; then
+        echo "CTestTestfile.cmake not found in $BUILD_TEST_DIR — tests not configured."
+        echo "Re-run cmake with -DWOWEE_BUILD_TESTS=ON"
+        exit 1
+    fi
+
+    echo "──────────────────────────────────────────────"
+    echo " Running unit tests [$TEST_LABEL]"
+    echo "──────────────────────────────────────────────"
+    if ! (cd "$BUILD_TEST_DIR" && ctest --output-on-failure); then
+        OVERALL_FAILED=1
+        echo ""
+        echo "One or more unit tests FAILED."
+    else
+        echo ""
+        echo "All unit tests passed."
+    fi
+fi
+
+# ---------------------------------------------------------------------------
+# ── LINT ───────────────────────────────────────────────────────────────────
+# ---------------------------------------------------------------------------
+if [[ $RUN_LINT -eq 0 ]]; then
+    exit $OVERALL_FAILED
+fi
+
+# Dependency check
 CLANG_TIDY=""
 for candidate in clang-tidy clang-tidy-18 clang-tidy-17 clang-tidy-16 clang-tidy-15 clang-tidy-14; do
     if command -v "$candidate" >/dev/null 2>&1; then
@@ -29,6 +120,9 @@ if [[ -z "$CLANG_TIDY" ]]; then
     exit 1
 fi
 
+echo "──────────────────────────────────────────────"
+echo " Running clang-tidy lint"
+echo "──────────────────────────────────────────────"
 echo "Using: $($CLANG_TIDY --version | head -1)"
 
 # run-clang-tidy runs checks in parallel; fall back to sequential if absent.
@@ -40,9 +134,7 @@ for candidate in run-clang-tidy run-clang-tidy-18 run-clang-tidy-17 run-clang-ti
     fi
 done
 
-# ---------------------------------------------------------------------------
 # Build database check
-# ---------------------------------------------------------------------------
 COMPILE_COMMANDS="$SCRIPT_DIR/build/compile_commands.json"
 if [[ ! -f "$COMPILE_COMMANDS" ]]; then
     echo "compile_commands.json not found at $COMPILE_COMMANDS"
@@ -108,7 +200,7 @@ if [[ "$FIX" == "1" ]]; then
     echo "Fix mode enabled — applying suggested fixes."
 fi
 
-FAILED=0
+LINT_FAILED=0
 
 if [[ -n "$RUN_CLANG_TIDY" ]]; then
     echo "Running via $RUN_CLANG_TIDY (parallel)..."
@@ -119,7 +211,7 @@ if [[ -n "$RUN_CLANG_TIDY" ]]; then
         -p "$SCRIPT_DIR/build" \
         $FIX_FLAG \
         "${EXTRA_RUN_ARGS[@]}" \
-        "$SRC_REGEX" || FAILED=$?
+        "$SRC_REGEX" || LINT_FAILED=$?
 else
     echo "run-clang-tidy not found; running sequentially..."
     for f in "${SOURCE_FILES[@]}"; do
@@ -127,18 +219,20 @@ else
             -p "$SCRIPT_DIR/build" \
             $FIX_FLAG \
             "${EXTRA_TIDY_ARGS[@]}" \
-            "$f" || FAILED=$?
+            "$f" || LINT_FAILED=$?
     done
 fi
 
 # ---------------------------------------------------------------------------
 # Result
 # ---------------------------------------------------------------------------
-if [[ $FAILED -ne 0 ]]; then
+if [[ $LINT_FAILED -ne 0 ]]; then
     echo ""
     echo "clang-tidy reported issues. Fix them or add suppressions in .clang-tidy."
-    exit 1
+    OVERALL_FAILED=1
+else
+    echo ""
+    echo "Lint passed."
 fi
 
-echo ""
-echo "Lint passed."
+exit $OVERALL_FAILED
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
index 00000000..7a25bf62
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,142 @@
+# Phase 0: Unit test infrastructure using Catch2 v3 (amalgamated)
+
+# Catch2 amalgamated as a library target
+add_library(catch2_main STATIC
+    ${CMAKE_SOURCE_DIR}/extern/catch2/catch_amalgamated.cpp
+)
+target_include_directories(catch2_main PUBLIC
+    ${CMAKE_SOURCE_DIR}/extern/catch2
+)
+# Catch2 v3 needs C++17 minimum
+target_compile_features(catch2_main PUBLIC cxx_std_17)
+
+# ── ASAN / UBSan propagation ────────────────────────────────
+# Collect all test target names so we can apply sanitizer flags at the end.
+set(ALL_TEST_TARGETS "")
+
+# Helper: register a test target for ASAN/UBSan if enabled.
+macro(register_test_target _target)
+    list(APPEND ALL_TEST_TARGETS ${_target})
+endmacro()
+
+# Shared source files used across multiple tests
+set(TEST_COMMON_SOURCES
+    ${CMAKE_SOURCE_DIR}/src/core/logger.cpp
+)
+
+# Include directories matching the main target
+set(TEST_INCLUDE_DIRS
+    ${CMAKE_SOURCE_DIR}/include
+    ${CMAKE_SOURCE_DIR}/src
+)
+set(TEST_SYSTEM_INCLUDE_DIRS
+    ${CMAKE_SOURCE_DIR}/extern
+)
+
+# ── test_packet ──────────────────────────────────────────────
+add_executable(test_packet
+    test_packet.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/network/packet.cpp
+)
+target_include_directories(test_packet PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_packet SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_packet PRIVATE catch2_main)
+add_test(NAME packet COMMAND test_packet)
+register_test_target(test_packet)
+
+# ── test_srp ─────────────────────────────────────────────────
+add_executable(test_srp
+    test_srp.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/auth/srp.cpp
+    ${CMAKE_SOURCE_DIR}/src/auth/big_num.cpp
+    ${CMAKE_SOURCE_DIR}/src/auth/crypto.cpp
+)
+target_include_directories(test_srp PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_srp SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_srp PRIVATE catch2_main OpenSSL::SSL OpenSSL::Crypto)
+add_test(NAME srp COMMAND test_srp)
+register_test_target(test_srp)
+
+# ── test_opcode_table ────────────────────────────────────────
+add_executable(test_opcode_table
+    test_opcode_table.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/game/opcode_table.cpp
+)
+target_include_directories(test_opcode_table PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_opcode_table SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_opcode_table PRIVATE catch2_main)
+add_test(NAME opcode_table COMMAND test_opcode_table)
+register_test_target(test_opcode_table)
+
+# ── test_entity ──────────────────────────────────────────────
+add_executable(test_entity
+    test_entity.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/game/entity.cpp
+)
+target_include_directories(test_entity PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_entity SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_entity PRIVATE catch2_main)
+add_test(NAME entity COMMAND test_entity)
+register_test_target(test_entity)
+
+# ── test_dbc_loader ──────────────────────────────────────────
+add_executable(test_dbc_loader
+    test_dbc_loader.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/pipeline/dbc_loader.cpp
+)
+target_include_directories(test_dbc_loader PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_dbc_loader SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_dbc_loader PRIVATE catch2_main)
+add_test(NAME dbc_loader COMMAND test_dbc_loader)
+register_test_target(test_dbc_loader)
+
+# ── test_m2_structs ──────────────────────────────────────────
+# Header-only struct layout tests — no source files needed
+add_executable(test_m2_structs
+    test_m2_structs.cpp
+)
+target_include_directories(test_m2_structs PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_m2_structs SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_m2_structs PRIVATE catch2_main)
+add_test(NAME m2_structs COMMAND test_m2_structs)
+register_test_target(test_m2_structs)
+
+# ── test_blp_loader ──────────────────────────────────────────
+add_executable(test_blp_loader
+    test_blp_loader.cpp
+    ${TEST_COMMON_SOURCES}
+    ${CMAKE_SOURCE_DIR}/src/pipeline/blp_loader.cpp
+)
+target_include_directories(test_blp_loader PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_blp_loader SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_blp_loader PRIVATE catch2_main)
+add_test(NAME blp_loader COMMAND test_blp_loader)
+register_test_target(test_blp_loader)
+
+# ── test_frustum ─────────────────────────────────────────────
+add_executable(test_frustum
+    test_frustum.cpp
+    ${CMAKE_SOURCE_DIR}/src/rendering/frustum.cpp
+)
+target_include_directories(test_frustum PRIVATE ${TEST_INCLUDE_DIRS})
+target_include_directories(test_frustum SYSTEM PRIVATE ${TEST_SYSTEM_INCLUDE_DIRS})
+target_link_libraries(test_frustum PRIVATE catch2_main)
+add_test(NAME frustum COMMAND test_frustum)
+register_test_target(test_frustum)
+
+# ── ASAN / UBSan for test targets ────────────────────────────
+if(WOWEE_ENABLE_ASAN AND NOT MSVC)
+    foreach(_t IN LISTS ALL_TEST_TARGETS)
+        target_compile_options(${_t} PRIVATE -fsanitize=address,undefined -fno-omit-frame-pointer)
+        target_link_options(${_t} PRIVATE -fsanitize=address,undefined)
+    endforeach()
+    # catch2_main must also be compiled with the same flags
+    target_compile_options(catch2_main PRIVATE -fsanitize=address,undefined -fno-omit-frame-pointer)
+    target_link_options(catch2_main PRIVATE -fsanitize=address,undefined)
+    message(STATUS "Test targets: ASAN + UBSan ENABLED")
+endif()
diff --git a/tests/test_blp_loader.cpp b/tests/test_blp_loader.cpp
new file mode 100644
index 00000000..b66073ad
--- /dev/null
+++ b/tests/test_blp_loader.cpp
@@ -0,0 +1,92 @@
+// Phase 0 – BLP loader tests: isValid, format names, invalid data handling
+#include <catch_amalgamated.hpp>
+#include "pipeline/blp_loader.hpp"
+
+using wowee::pipeline::BLPLoader;
+using wowee::pipeline::BLPImage;
+using wowee::pipeline::BLPFormat;
+using wowee::pipeline::BLPCompression;
+
+TEST_CASE("BLPImage default is invalid", "[blp]") {
+    BLPImage img;
+    REQUIRE_FALSE(img.isValid());
+    REQUIRE(img.width == 0);
+    REQUIRE(img.height == 0);
+    REQUIRE(img.format == BLPFormat::UNKNOWN);
+    REQUIRE(img.compression == BLPCompression::NONE);
+}
+
+TEST_CASE("BLPImage isValid with data", "[blp]") {
+    BLPImage img;
+    img.width = 64;
+    img.height = 64;
+    img.data.resize(64 * 64 * 4, 0xFF);  // RGBA
+    REQUIRE(img.isValid());
+}
+
+TEST_CASE("BLPImage isValid requires non-empty data", "[blp]") {
+    BLPImage img;
+    img.width = 64;
+    img.height = 64;
+    // data is empty
+    REQUIRE_FALSE(img.isValid());
+}
+
+TEST_CASE("BLPLoader::load empty data returns invalid", "[blp]") {
+    std::vector<uint8_t> empty;
+    auto img = BLPLoader::load(empty);
+    REQUIRE_FALSE(img.isValid());
+}
+
+TEST_CASE("BLPLoader::load too small data returns invalid", "[blp]") {
+    std::vector<uint8_t> tiny = {0x42, 0x4C, 0x50}; // BLP but truncated
+    auto img = BLPLoader::load(tiny);
+    REQUIRE_FALSE(img.isValid());
+}
+
+TEST_CASE("BLPLoader::load invalid magic returns invalid", "[blp]") {
+    // Provide enough bytes but with wrong magic
+    std::vector<uint8_t> bad(256, 0);
+    bad[0] = 'N'; bad[1] = 'O'; bad[2] = 'T'; bad[3] = '!';
+    auto img = BLPLoader::load(bad);
+    REQUIRE_FALSE(img.isValid());
+}
+
+TEST_CASE("BLPLoader getFormatName returns non-null", "[blp]") {
+    REQUIRE(BLPLoader::getFormatName(BLPFormat::UNKNOWN) != nullptr);
+    REQUIRE(BLPLoader::getFormatName(BLPFormat::BLP1) != nullptr);
+    REQUIRE(BLPLoader::getFormatName(BLPFormat::BLP2) != nullptr);
+
+    // Check that names are distinct
+    REQUIRE(std::string(BLPLoader::getFormatName(BLPFormat::BLP1)) !=
+            std::string(BLPLoader::getFormatName(BLPFormat::BLP2)));
+}
+
+TEST_CASE("BLPLoader getCompressionName returns non-null", "[blp]") {
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::NONE) != nullptr);
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::DXT1) != nullptr);
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::DXT3) != nullptr);
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::DXT5) != nullptr);
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::PALETTE) != nullptr);
+    REQUIRE(BLPLoader::getCompressionName(BLPCompression::ARGB8888) != nullptr);
+
+    // Check that DXT names differ
+    REQUIRE(std::string(BLPLoader::getCompressionName(BLPCompression::DXT1)) !=
+            std::string(BLPLoader::getCompressionName(BLPCompression::DXT5)));
+}
+
+TEST_CASE("BLPImage mipmap storage", "[blp]") {
+    BLPImage img;
+    img.width = 128;
+    img.height = 128;
+    img.data.resize(128 * 128 * 4, 0);
+    img.mipLevels = 3;
+
+    // Add mipmap data
+    img.mipmaps.push_back(std::vector<uint8_t>(64 * 64 * 4, 0));
+    img.mipmaps.push_back(std::vector<uint8_t>(32 * 32 * 4, 0));
+    img.mipmaps.push_back(std::vector<uint8_t>(16 * 16 * 4, 0));
+
+    REQUIRE(img.isValid());
+    REQUIRE(img.mipmaps.size() == 3);
+}
diff --git a/tests/test_dbc_loader.cpp b/tests/test_dbc_loader.cpp
new file mode 100644
index 00000000..6afa0b44
--- /dev/null
+++ b/tests/test_dbc_loader.cpp
@@ -0,0 +1,208 @@
+// Phase 0 – DBC binary parsing tests with synthetic data
+#include <catch_amalgamated.hpp>
+#include "pipeline/dbc_loader.hpp"
+#include <cstring>
+
+using wowee::pipeline::DBCFile;
+
+// Build a minimal valid DBC in memory:
+//   Header: "WDBC" + recordCount(uint32) + fieldCount(uint32) + recordSize(uint32) + stringBlockSize(uint32)
+//   Records: contiguous fixed-size rows
+//   String block: null-terminated strings
+static std::vector<uint8_t> buildSyntheticDBC(
+    uint32_t numRecords, uint32_t numFields,
+    const std::vector<std::vector<uint32_t>>& records,
+    const std::string& stringBlock)
+{
+    const uint32_t recordSize = numFields * 4;
+    const uint32_t stringBlockSize = static_cast<uint32_t>(stringBlock.size());
+
+    std::vector<uint8_t> data;
+    // Reserve enough space
+    data.reserve(20 + numRecords * recordSize + stringBlockSize);
+
+    // Magic
+    data.push_back('W'); data.push_back('D'); data.push_back('B'); data.push_back('C');
+
+    auto writeU32 = [&](uint32_t v) {
+        data.push_back(static_cast<uint8_t>(v & 0xFF));
+        data.push_back(static_cast<uint8_t>((v >> 8) & 0xFF));
+        data.push_back(static_cast<uint8_t>((v >> 16) & 0xFF));
+        data.push_back(static_cast<uint8_t>((v >> 24) & 0xFF));
+    };
+
+    writeU32(numRecords);
+    writeU32(numFields);
+    writeU32(recordSize);
+    writeU32(stringBlockSize);
+
+    // Records
+    for (const auto& rec : records) {
+        for (uint32_t field : rec) {
+            writeU32(field);
+        }
+    }
+
+    // String block
+    for (char c : stringBlock) {
+        data.push_back(static_cast<uint8_t>(c));
+    }
+
+    return data;
+}
+
+TEST_CASE("DBCFile default state", "[dbc]") {
+    DBCFile dbc;
+    REQUIRE_FALSE(dbc.isLoaded());
+    REQUIRE(dbc.getRecordCount() == 0);
+    REQUIRE(dbc.getFieldCount() == 0);
+}
+
+TEST_CASE("DBCFile load valid DBC", "[dbc]") {
+    // 2 records, 3 fields each: [id, intVal, stringOffset]
+    // String block: "\0Hello\0World\0" → offset 0="" 1="Hello" 7="World"
+    std::string strings;
+    strings += '\0';             // offset 0: empty string
+    strings += "Hello";
+    strings += '\0';             // offset 1-6: "Hello"
+    strings += "World";
+    strings += '\0';             // offset 7-12: "World"
+
+    auto data = buildSyntheticDBC(2, 3,
+        {
+            {1, 100, 1},   // Record 0: id=1, intVal=100, stringOffset=1 → "Hello"
+            {2, 200, 7},   // Record 1: id=2, intVal=200, stringOffset=7 → "World"
+        },
+        strings);
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+    REQUIRE(dbc.isLoaded());
+    REQUIRE(dbc.getRecordCount() == 2);
+    REQUIRE(dbc.getFieldCount() == 3);
+    REQUIRE(dbc.getRecordSize() == 12);
+    REQUIRE(dbc.getStringBlockSize() == strings.size());
+}
+
+TEST_CASE("DBCFile getUInt32 and getInt32", "[dbc]") {
+    auto data = buildSyntheticDBC(1, 2,
+        { {42, 0xFFFFFFFF} },
+        std::string(1, '\0'));
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+
+    REQUIRE(dbc.getUInt32(0, 0) == 42);
+    REQUIRE(dbc.getUInt32(0, 1) == 0xFFFFFFFF);
+    REQUIRE(dbc.getInt32(0, 1) == -1);
+}
+
+TEST_CASE("DBCFile getFloat", "[dbc]") {
+    float testVal = 3.14f;
+    uint32_t bits;
+    std::memcpy(&bits, &testVal, 4);
+
+    auto data = buildSyntheticDBC(1, 2,
+        { {1, bits} },
+        std::string(1, '\0'));
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+    REQUIRE(dbc.getFloat(0, 1) == Catch::Approx(3.14f));
+}
+
+TEST_CASE("DBCFile getString", "[dbc]") {
+    std::string strings;
+    strings += '\0';
+    strings += "TestString";
+    strings += '\0';
+
+    auto data = buildSyntheticDBC(1, 2,
+        { {1, 1} },  // field 1 = string offset 1 → "TestString"
+        strings);
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+    REQUIRE(dbc.getString(0, 1) == "TestString");
+}
+
+TEST_CASE("DBCFile getStringView", "[dbc]") {
+    std::string strings;
+    strings += '\0';
+    strings += "ViewTest";
+    strings += '\0';
+
+    auto data = buildSyntheticDBC(1, 2,
+        { {1, 1} },
+        strings);
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+    REQUIRE(dbc.getStringView(0, 1) == "ViewTest");
+}
+
+TEST_CASE("DBCFile findRecordById", "[dbc]") {
+    auto data = buildSyntheticDBC(3, 2,
+        {
+            {10, 100},
+            {20, 200},
+            {30, 300},
+        },
+        std::string(1, '\0'));
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+
+    REQUIRE(dbc.findRecordById(10) == 0);
+    REQUIRE(dbc.findRecordById(20) == 1);
+    REQUIRE(dbc.findRecordById(30) == 2);
+    REQUIRE(dbc.findRecordById(99) == -1);
+}
+
+TEST_CASE("DBCFile getRecord returns pointer", "[dbc]") {
+    auto data = buildSyntheticDBC(1, 2,
+        { {0xAB, 0xCD} },
+        std::string(1, '\0'));
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+
+    const uint8_t* rec = dbc.getRecord(0);
+    REQUIRE(rec != nullptr);
+
+    // First field should be 0xAB in little-endian
+    uint32_t val;
+    std::memcpy(&val, rec, 4);
+    REQUIRE(val == 0xAB);
+}
+
+TEST_CASE("DBCFile load too small data", "[dbc]") {
+    std::vector<uint8_t> tiny = {'W', 'D', 'B'};
+    DBCFile dbc;
+    REQUIRE_FALSE(dbc.load(tiny));
+}
+
+TEST_CASE("DBCFile load wrong magic", "[dbc]") {
+    auto data = buildSyntheticDBC(0, 1, {}, std::string(1, '\0'));
+    // Corrupt magic
+    data[0] = 'X';
+
+    DBCFile dbc;
+    REQUIRE_FALSE(dbc.load(data));
+}
+
+TEST_CASE("DBCFile getStringByOffset", "[dbc]") {
+    std::string strings;
+    strings += '\0';
+    strings += "Offset5";  // This would be at offset 1 actually, let me be precise
+    strings += '\0';
+
+    auto data = buildSyntheticDBC(1, 1,
+        { {0} },
+        strings);
+
+    DBCFile dbc;
+    REQUIRE(dbc.load(data));
+    REQUIRE(dbc.getStringByOffset(1) == "Offset5");
+    REQUIRE(dbc.getStringByOffset(0).empty());
+}
diff --git a/tests/test_entity.cpp b/tests/test_entity.cpp
new file mode 100644
index 00000000..0d30f6e2
--- /dev/null
+++ b/tests/test_entity.cpp
@@ -0,0 +1,220 @@
+// Phase 0 – Entity, Unit, Player, GameObject, EntityManager tests
+#include <catch_amalgamated.hpp>
+#include "game/entity.hpp"
+#include <memory>
+
+using namespace wowee::game;
+
+TEST_CASE("Entity default construction", "[entity]") {
+    Entity e;
+    REQUIRE(e.getGuid() == 0);
+    REQUIRE(e.getType() == ObjectType::OBJECT);
+    REQUIRE(e.getX() == 0.0f);
+    REQUIRE(e.getY() == 0.0f);
+    REQUIRE(e.getZ() == 0.0f);
+    REQUIRE(e.getOrientation() == 0.0f);
+}
+
+TEST_CASE("Entity GUID constructor", "[entity]") {
+    Entity e(0xDEADBEEF);
+    REQUIRE(e.getGuid() == 0xDEADBEEF);
+}
+
+TEST_CASE("Entity position set/get", "[entity]") {
+    Entity e;
+    e.setPosition(1.0f, 2.0f, 3.0f, 1.57f);
+    REQUIRE(e.getX() == Catch::Approx(1.0f));
+    REQUIRE(e.getY() == Catch::Approx(2.0f));
+    REQUIRE(e.getZ() == Catch::Approx(3.0f));
+    REQUIRE(e.getOrientation() == Catch::Approx(1.57f));
+}
+
+TEST_CASE("Entity field set/get/has", "[entity]") {
+    Entity e;
+    REQUIRE_FALSE(e.hasField(10));
+
+    e.setField(10, 0xCAFE);
+    REQUIRE(e.hasField(10));
+    REQUIRE(e.getField(10) == 0xCAFE);
+
+    // Overwrite
+    e.setField(10, 0xBEEF);
+    REQUIRE(e.getField(10) == 0xBEEF);
+
+    // Non-existent returns 0
+    REQUIRE(e.getField(999) == 0);
+}
+
+TEST_CASE("Unit construction and type", "[entity]") {
+    Unit u;
+    REQUIRE(u.getType() == ObjectType::UNIT);
+
+    Unit u2(0x123);
+    REQUIRE(u2.getGuid() == 0x123);
+    REQUIRE(u2.getType() == ObjectType::UNIT);
+}
+
+TEST_CASE("Unit name", "[entity]") {
+    Unit u;
+    REQUIRE(u.getName().empty());
+    u.setName("Hogger");
+    REQUIRE(u.getName() == "Hogger");
+}
+
+TEST_CASE("Unit health", "[entity]") {
+    Unit u;
+    REQUIRE(u.getHealth() == 0);
+    REQUIRE(u.getMaxHealth() == 0);
+
+    u.setHealth(500);
+    u.setMaxHealth(1000);
+    REQUIRE(u.getHealth() == 500);
+    REQUIRE(u.getMaxHealth() == 1000);
+}
+
+TEST_CASE("Unit power by type", "[entity]") {
+    Unit u;
+    u.setPowerType(0); // mana
+    u.setPower(200);
+    u.setMaxPower(500);
+
+    REQUIRE(u.getPower() == 200);
+    REQUIRE(u.getMaxPower() == 500);
+    REQUIRE(u.getPowerByType(0) == 200);
+    REQUIRE(u.getMaxPowerByType(0) == 500);
+
+    // Set rage (type 1)
+    u.setPowerByType(1, 50);
+    u.setMaxPowerByType(1, 100);
+    REQUIRE(u.getPowerByType(1) == 50);
+    REQUIRE(u.getMaxPowerByType(1) == 100);
+
+    // Out of bounds clamps
+    REQUIRE(u.getPowerByType(7) == 0);
+    REQUIRE(u.getMaxPowerByType(7) == 0);
+}
+
+TEST_CASE("Unit level, entry, displayId", "[entity]") {
+    Unit u;
+    REQUIRE(u.getLevel() == 1); // default
+    u.setLevel(80);
+    REQUIRE(u.getLevel() == 80);
+
+    u.setEntry(1234);
+    REQUIRE(u.getEntry() == 1234);
+
+    u.setDisplayId(5678);
+    REQUIRE(u.getDisplayId() == 5678);
+}
+
+TEST_CASE("Unit flags", "[entity]") {
+    Unit u;
+    u.setUnitFlags(0x01);
+    REQUIRE(u.getUnitFlags() == 0x01);
+
+    u.setDynamicFlags(0x02);
+    REQUIRE(u.getDynamicFlags() == 0x02);
+
+    u.setNpcFlags(0x04);
+    REQUIRE(u.getNpcFlags() == 0x04);
+    REQUIRE(u.isInteractable());
+
+    u.setNpcFlags(0);
+    REQUIRE_FALSE(u.isInteractable());
+}
+
+TEST_CASE("Unit faction and hostility", "[entity]") {
+    Unit u;
+    u.setFactionTemplate(14); // Undercity
+    REQUIRE(u.getFactionTemplate() == 14);
+
+    REQUIRE_FALSE(u.isHostile());
+    u.setHostile(true);
+    REQUIRE(u.isHostile());
+}
+
+TEST_CASE("Unit mount display ID", "[entity]") {
+    Unit u;
+    REQUIRE(u.getMountDisplayId() == 0);
+    u.setMountDisplayId(14374);
+    REQUIRE(u.getMountDisplayId() == 14374);
+}
+
+TEST_CASE("Player inherits Unit", "[entity]") {
+    Player p(0xABC);
+    REQUIRE(p.getType() == ObjectType::PLAYER);
+    REQUIRE(p.getGuid() == 0xABC);
+
+    // Player inherits Unit name — regression test for the shadowed-field fix
+    p.setName("Arthas");
+    REQUIRE(p.getName() == "Arthas");
+
+    p.setLevel(80);
+    REQUIRE(p.getLevel() == 80);
+}
+
+TEST_CASE("GameObject construction", "[entity]") {
+    GameObject go(0x999);
+    REQUIRE(go.getType() == ObjectType::GAMEOBJECT);
+    REQUIRE(go.getGuid() == 0x999);
+
+    go.setName("Mailbox");
+    REQUIRE(go.getName() == "Mailbox");
+
+    go.setEntry(42);
+    REQUIRE(go.getEntry() == 42);
+
+    go.setDisplayId(100);
+    REQUIRE(go.getDisplayId() == 100);
+}
+
+TEST_CASE("EntityManager add/get/has/remove", "[entity]") {
+    EntityManager mgr;
+    REQUIRE(mgr.getEntityCount() == 0);
+
+    auto unit = std::make_shared<Unit>(1);
+    unit->setName("TestUnit");
+    mgr.addEntity(1, unit);
+
+    REQUIRE(mgr.getEntityCount() == 1);
+    REQUIRE(mgr.hasEntity(1));
+    REQUIRE_FALSE(mgr.hasEntity(2));
+
+    auto retrieved = mgr.getEntity(1);
+    REQUIRE(retrieved != nullptr);
+    REQUIRE(retrieved->getGuid() == 1);
+
+    mgr.removeEntity(1);
+    REQUIRE_FALSE(mgr.hasEntity(1));
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager clear", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(1, std::make_shared<Entity>(1));
+    mgr.addEntity(2, std::make_shared<Entity>(2));
+    REQUIRE(mgr.getEntityCount() == 2);
+
+    mgr.clear();
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager null entity rejected", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(1, nullptr);
+    // Null should be rejected (logged warning, not stored)
+    REQUIRE(mgr.getEntityCount() == 0);
+}
+
+TEST_CASE("EntityManager getEntities returns all", "[entity]") {
+    EntityManager mgr;
+    mgr.addEntity(10, std::make_shared<Unit>(10));
+    mgr.addEntity(20, std::make_shared<Player>(20));
+    mgr.addEntity(30, std::make_shared<GameObject>(30));
+
+    const auto& all = mgr.getEntities();
+    REQUIRE(all.size() == 3);
+    REQUIRE(all.count(10) == 1);
+    REQUIRE(all.count(20) == 1);
+    REQUIRE(all.count(30) == 1);
+}
diff --git a/tests/test_frustum.cpp b/tests/test_frustum.cpp
new file mode 100644
index 00000000..19d67a8f
--- /dev/null
+++ b/tests/test_frustum.cpp
@@ -0,0 +1,132 @@
+// Phase 0 – Frustum plane extraction and intersection tests
+#include <catch_amalgamated.hpp>
+#include "rendering/frustum.hpp"
+
+#include <glm/glm.hpp>
+#include <glm/gtc/matrix_transform.hpp>
+
+using wowee::rendering::Frustum;
+using wowee::rendering::Plane;
+
+TEST_CASE("Plane distanceToPoint", "[frustum]") {
+    // Plane facing +Y at y=5
+    Plane p(glm::vec3(0.0f, 1.0f, 0.0f), -5.0f);
+
+    // Point at y=10 → distance = 10 + (-5) = 5 (in front)
+    REQUIRE(p.distanceToPoint(glm::vec3(0, 10, 0)) == Catch::Approx(5.0f));
+
+    // Point at y=5 → distance = 0 (on plane)
+    REQUIRE(p.distanceToPoint(glm::vec3(0, 5, 0)) == Catch::Approx(0.0f));
+
+    // Point at y=0 → distance = -5 (behind)
+    REQUIRE(p.distanceToPoint(glm::vec3(0, 0, 0)) == Catch::Approx(-5.0f));
+}
+
+TEST_CASE("Frustum extractFromMatrix with identity", "[frustum]") {
+    Frustum f;
+    f.extractFromMatrix(glm::mat4(1.0f));
+
+    // Identity matrix gives clip-space frustum: [-1,1]^3 (or [0,1] for z)
+    // The origin should be inside
+    REQUIRE(f.containsPoint(glm::vec3(0.0f, 0.0f, 0.5f)));
+}
+
+TEST_CASE("Frustum containsPoint perspective", "[frustum]") {
+    // Create a typical perspective projection and look-at
+    glm::mat4 proj = glm::perspective(glm::radians(90.0f), 1.0f, 0.1f, 100.0f);
+    glm::mat4 view = glm::lookAt(
+        glm::vec3(0, 0, 0),   // eye
+        glm::vec3(0, 0, -1),  // center (looking -Z)
+        glm::vec3(0, 1, 0)    // up
+    );
+    glm::mat4 vp = proj * view;
+
+    Frustum f;
+    f.extractFromMatrix(vp);
+
+    // Point in front (at -Z)
+    REQUIRE(f.containsPoint(glm::vec3(0, 0, -10)));
+
+    // Point behind camera (at +Z) should be outside
+    REQUIRE_FALSE(f.containsPoint(glm::vec3(0, 0, 10)));
+
+    // Point very far away inside the frustum
+    REQUIRE(f.containsPoint(glm::vec3(0, 0, -50)));
+
+    // Point beyond far plane
+    REQUIRE_FALSE(f.containsPoint(glm::vec3(0, 0, -200)));
+}
+
+TEST_CASE("Frustum intersectsSphere", "[frustum]") {
+    glm::mat4 proj = glm::perspective(glm::radians(60.0f), 1.0f, 1.0f, 100.0f);
+    glm::mat4 view = glm::lookAt(
+        glm::vec3(0, 0, 0),
+        glm::vec3(0, 0, -1),
+        glm::vec3(0, 1, 0)
+    );
+    Frustum f;
+    f.extractFromMatrix(proj * view);
+
+    // Sphere clearly inside
+    REQUIRE(f.intersectsSphere(glm::vec3(0, 0, -10), 1.0f));
+
+    // Sphere behind camera
+    REQUIRE_FALSE(f.intersectsSphere(glm::vec3(0, 0, 50), 1.0f));
+
+    // Large sphere that straddles the near plane
+    REQUIRE(f.intersectsSphere(glm::vec3(0, 0, 0), 5.0f));
+
+    // Sphere at edge of frustum — large radius should still intersect
+    REQUIRE(f.intersectsSphere(glm::vec3(0, 0, -105), 10.0f));
+}
+
+TEST_CASE("Frustum intersectsAABB", "[frustum]") {
+    glm::mat4 proj = glm::perspective(glm::radians(60.0f), 1.0f, 1.0f, 100.0f);
+    glm::mat4 view = glm::lookAt(
+        glm::vec3(0, 0, 0),
+        glm::vec3(0, 0, -1),
+        glm::vec3(0, 1, 0)
+    );
+    Frustum f;
+    f.extractFromMatrix(proj * view);
+
+    // Box inside frustum
+    REQUIRE(f.intersectsAABB(glm::vec3(-1, -1, -11), glm::vec3(1, 1, -9)));
+
+    // Box behind camera
+    REQUIRE_FALSE(f.intersectsAABB(glm::vec3(-1, -1, 5), glm::vec3(1, 1, 10)));
+
+    // Box beyond far plane
+    REQUIRE_FALSE(f.intersectsAABB(glm::vec3(-1, -1, -200), glm::vec3(1, 1, -150)));
+
+    // Large box straddling near/far
+    REQUIRE(f.intersectsAABB(glm::vec3(-5, -5, -50), glm::vec3(5, 5, 0)));
+}
+
+TEST_CASE("Frustum getPlane returns 6 planes", "[frustum]") {
+    glm::mat4 proj = glm::perspective(glm::radians(90.0f), 1.0f, 1.0f, 100.0f);
+    Frustum f;
+    f.extractFromMatrix(proj);
+
+    // Access all 6 planes — should not crash
+    for (int i = 0; i < 6; ++i) {
+        const auto& p = f.getPlane(static_cast<Frustum::Side>(i));
+        // Normal should be a unit vector (after normalization)
+        float len = glm::length(p.normal);
+        REQUIRE(len == Catch::Approx(1.0f).margin(0.01f));
+    }
+}
+
+TEST_CASE("Frustum box far right is outside", "[frustum]") {
+    glm::mat4 proj = glm::perspective(glm::radians(45.0f), 1.0f, 1.0f, 100.0f);
+    glm::mat4 view = glm::lookAt(
+        glm::vec3(0, 0, 0),
+        glm::vec3(0, 0, -1),
+        glm::vec3(0, 1, 0)
+    );
+    Frustum f;
+    f.extractFromMatrix(proj * view);
+
+    // Box far off to the right — outside the frustum
+    REQUIRE_FALSE(f.intersectsAABB(glm::vec3(200, 0, -10), glm::vec3(201, 1, -9)));
+}
diff --git a/tests/test_m2_structs.cpp b/tests/test_m2_structs.cpp
new file mode 100644
index 00000000..2f9b0a1c
--- /dev/null
+++ b/tests/test_m2_structs.cpp
@@ -0,0 +1,164 @@
+// Phase 0 – M2 struct layout and field tests (header-only, no loader source)
+#include <catch_amalgamated.hpp>
+#include "pipeline/m2_loader.hpp"
+#include <cstring>
+
+using namespace wowee::pipeline;
+
+TEST_CASE("M2Sequence fields are default-initialized", "[m2]") {
+    M2Sequence seq{};
+    REQUIRE(seq.id == 0);
+    REQUIRE(seq.duration == 0);
+    REQUIRE(seq.movingSpeed == 0.0f);
+    REQUIRE(seq.flags == 0);
+    REQUIRE(seq.blendTime == 0);
+    REQUIRE(seq.boundRadius == 0.0f);
+}
+
+TEST_CASE("M2AnimationTrack hasData", "[m2]") {
+    M2AnimationTrack track;
+    REQUIRE_FALSE(track.hasData());
+
+    track.sequences.push_back({});
+    REQUIRE(track.hasData());
+}
+
+TEST_CASE("M2AnimationTrack default interpolation", "[m2]") {
+    M2AnimationTrack track;
+    REQUIRE(track.interpolationType == 0);
+    REQUIRE(track.globalSequence == -1);
+}
+
+TEST_CASE("M2Bone parent defaults to root", "[m2]") {
+    M2Bone bone{};
+    bone.parentBone = -1;
+    REQUIRE(bone.parentBone == -1);
+    REQUIRE(bone.keyBoneId == 0);
+}
+
+TEST_CASE("M2Vertex layout", "[m2]") {
+    M2Vertex vert{};
+    vert.position = glm::vec3(1.0f, 2.0f, 3.0f);
+    vert.boneWeights[0] = 255;
+    vert.boneWeights[1] = 0;
+    vert.boneWeights[2] = 0;
+    vert.boneWeights[3] = 0;
+    vert.boneIndices[0] = 5;
+    vert.normal = glm::vec3(0.0f, 1.0f, 0.0f);
+    vert.texCoords[0] = glm::vec2(0.5f, 0.5f);
+
+    REQUIRE(vert.position.x == 1.0f);
+    REQUIRE(vert.boneWeights[0] == 255);
+    REQUIRE(vert.boneIndices[0] == 5);
+    REQUIRE(vert.normal.y == 1.0f);
+    REQUIRE(vert.texCoords[0].x == 0.5f);
+}
+
+TEST_CASE("M2Texture stores filename", "[m2]") {
+    M2Texture tex{};
+    tex.type = 1;
+    tex.filename = "Creature\\Hogger\\Hogger.blp";
+    REQUIRE(tex.filename == "Creature\\Hogger\\Hogger.blp");
+}
+
+TEST_CASE("M2Batch submesh fields", "[m2]") {
+    M2Batch batch{};
+    batch.skinSectionIndex = 3;
+    batch.textureCount = 2;
+    batch.indexStart = 100;
+    batch.indexCount = 300;
+    batch.vertexStart = 0;
+    batch.vertexCount = 150;
+    batch.submeshId = 0;
+    batch.submeshLevel = 0;
+
+    REQUIRE(batch.skinSectionIndex == 3);
+    REQUIRE(batch.textureCount == 2);
+    REQUIRE(batch.indexCount == 300);
+    REQUIRE(batch.vertexCount == 150);
+}
+
+TEST_CASE("M2Material blend modes", "[m2]") {
+    M2Material mat{};
+    mat.flags = 0;
+    mat.blendMode = 2;  // Alpha blend
+    REQUIRE(mat.blendMode == 2);
+
+    mat.blendMode = 0;  // Opaque
+    REQUIRE(mat.blendMode == 0);
+}
+
+TEST_CASE("M2Model isValid", "[m2]") {
+    M2Model model{};
+    REQUIRE_FALSE(model.isValid()); // no vertices or indices
+
+    model.vertices.push_back({});
+    REQUIRE_FALSE(model.isValid()); // vertices but no indices
+
+    model.indices.push_back(0);
+    REQUIRE(model.isValid()); // both present
+}
+
+TEST_CASE("M2Model bounding box", "[m2]") {
+    M2Model model{};
+    model.boundMin = glm::vec3(-1.0f, -2.0f, -3.0f);
+    model.boundMax = glm::vec3(1.0f, 2.0f, 3.0f);
+    model.boundRadius = 5.0f;
+
+    glm::vec3 center = (model.boundMin + model.boundMax) * 0.5f;
+    REQUIRE(center.x == Catch::Approx(0.0f));
+    REQUIRE(center.y == Catch::Approx(0.0f));
+    REQUIRE(center.z == Catch::Approx(0.0f));
+}
+
+TEST_CASE("M2ParticleEmitter defaults", "[m2]") {
+    M2ParticleEmitter emitter{};
+    emitter.textureRows = 1;
+    emitter.textureCols = 1;
+    emitter.enabled = true;
+    REQUIRE(emitter.textureRows == 1);
+    REQUIRE(emitter.textureCols == 1);
+    REQUIRE(emitter.enabled);
+}
+
+TEST_CASE("M2RibbonEmitter defaults", "[m2]") {
+    M2RibbonEmitter ribbon{};
+    REQUIRE(ribbon.edgesPerSecond == Catch::Approx(15.0f));
+    REQUIRE(ribbon.edgeLifetime == Catch::Approx(0.5f));
+    REQUIRE(ribbon.gravity == Catch::Approx(0.0f));
+}
+
+TEST_CASE("M2Attachment position", "[m2]") {
+    M2Attachment att{};
+    att.id = 1;  // Right hand
+    att.bone = 42;
+    att.position = glm::vec3(0.1f, 0.2f, 0.3f);
+
+    REQUIRE(att.id == 1);
+    REQUIRE(att.bone == 42);
+    REQUIRE(att.position.z == Catch::Approx(0.3f));
+}
+
+TEST_CASE("M2Model collections", "[m2]") {
+    M2Model model{};
+
+    // Bones
+    model.bones.push_back({});
+    model.bones[0].parentBone = -1;
+    model.bones[0].pivot = glm::vec3(0, 0, 0);
+
+    // Sequences
+    model.sequences.push_back({});
+    model.sequences[0].id = 0; // Stand
+    model.sequences[0].duration = 1000;
+
+    // Textures
+    model.textures.push_back({});
+    model.textures[0].type = 0;
+    model.textures[0].filename = "test.blp";
+
+    REQUIRE(model.bones.size() == 1);
+    REQUIRE(model.sequences.size() == 1);
+    REQUIRE(model.textures.size() == 1);
+    REQUIRE(model.sequences[0].duration == 1000);
+}
diff --git a/tests/test_opcode_table.cpp b/tests/test_opcode_table.cpp
new file mode 100644
index 00000000..ee123bed
--- /dev/null
+++ b/tests/test_opcode_table.cpp
@@ -0,0 +1,118 @@
+// Phase 0 – OpcodeTable load from JSON, toWire/fromWire mapping
+#include <catch_amalgamated.hpp>
+#include "game/opcode_table.hpp"
+#include <fstream>
+#include <filesystem>
+#include <cstdio>
+
+using wowee::game::OpcodeTable;
+using wowee::game::LogicalOpcode;
+
+// Helper: write a temporary JSON file and return its path.
+// Uses the executable's directory to avoid permission issues.
+static std::string writeTempJson(const std::string& content) {
+    auto path = std::filesystem::temp_directory_path() / "wowee_test_opcodes.json";
+    std::ofstream f(path);
+    f << content;
+    f.close();
+    return path.string();
+}
+
+TEST_CASE("OpcodeTable loadFromJson basic mapping", "[opcode_table]") {
+    // CMSG_PING and SMSG_PONG are canonical opcodes present in the generated enum.
+    std::string json = R"({
+        "CMSG_PING": "0x1DC",
+        "SMSG_PONG": "0x1DD"
+    })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    REQUIRE(table.loadFromJson(path));
+
+    REQUIRE(table.size() == 2);
+    REQUIRE(table.hasOpcode(LogicalOpcode::CMSG_PING));
+    REQUIRE(table.toWire(LogicalOpcode::CMSG_PING) == 0x1DC);
+    REQUIRE(table.toWire(LogicalOpcode::SMSG_PONG) == 0x1DD);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable fromWire reverse lookup", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    auto result = table.fromWire(0x1DC);
+    REQUIRE(result.has_value());
+    REQUIRE(*result == LogicalOpcode::CMSG_PING);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable unknown wire returns nullopt", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    auto result = table.fromWire(0x9999);
+    REQUIRE_FALSE(result.has_value());
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable unknown logical returns 0xFFFF", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    table.loadFromJson(path);
+
+    // SMSG_AUTH_CHALLENGE should not be in this table
+    REQUIRE(table.toWire(LogicalOpcode::SMSG_AUTH_CHALLENGE) == 0xFFFF);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("OpcodeTable loadFromJson nonexistent file", "[opcode_table]") {
+    OpcodeTable table;
+    REQUIRE_FALSE(table.loadFromJson("/nonexistent/path/opcodes.json"));
+    REQUIRE(table.size() == 0);
+}
+
+TEST_CASE("OpcodeTable logicalToName returns enum name", "[opcode_table]") {
+    const char* name = OpcodeTable::logicalToName(LogicalOpcode::CMSG_PING);
+    REQUIRE(name != nullptr);
+    REQUIRE(std::string(name) == "CMSG_PING");
+}
+
+TEST_CASE("OpcodeTable decimal wire values", "[opcode_table]") {
+    std::string json = R"({ "CMSG_PING": "476" })";
+    auto path = writeTempJson(json);
+
+    OpcodeTable table;
+    REQUIRE(table.loadFromJson(path));
+    REQUIRE(table.toWire(LogicalOpcode::CMSG_PING) == 476);
+
+    std::remove(path.c_str());
+}
+
+TEST_CASE("Global active opcode table", "[opcode_table]") {
+    OpcodeTable table;
+    std::string json = R"({ "CMSG_PING": "0x1DC" })";
+    auto path = writeTempJson(json);
+    table.loadFromJson(path);
+
+    wowee::game::setActiveOpcodeTable(&table);
+    REQUIRE(wowee::game::getActiveOpcodeTable() == &table);
+    REQUIRE(wowee::game::wireOpcode(LogicalOpcode::CMSG_PING) == 0x1DC);
+
+    // Reset
+    wowee::game::setActiveOpcodeTable(nullptr);
+    REQUIRE(wowee::game::wireOpcode(LogicalOpcode::CMSG_PING) == 0xFFFF);
+
+    std::remove(path.c_str());
+}
diff --git a/tests/test_packet.cpp b/tests/test_packet.cpp
new file mode 100644
index 00000000..16f2032c
--- /dev/null
+++ b/tests/test_packet.cpp
@@ -0,0 +1,192 @@
+// Phase 0 – Packet read/write round-trip, packed GUID, bounds checks
+#include <catch_amalgamated.hpp>
+#include "network/packet.hpp"
+
+using wowee::network::Packet;
+
+TEST_CASE("Packet default constructor", "[packet]") {
+    Packet p;
+    REQUIRE(p.getOpcode() == 0);
+    REQUIRE(p.getSize() == 0);
+    REQUIRE(p.getReadPos() == 0);
+    REQUIRE(p.getRemainingSize() == 0);
+    REQUIRE_FALSE(p.hasData());
+}
+
+TEST_CASE("Packet opcode constructor", "[packet]") {
+    Packet p(0x1DC);
+    REQUIRE(p.getOpcode() == 0x1DC);
+    REQUIRE(p.getSize() == 0);
+}
+
+TEST_CASE("Packet write/read UInt8 round-trip", "[packet]") {
+    Packet p(1);
+    p.writeUInt8(0);
+    p.writeUInt8(127);
+    p.writeUInt8(255);
+    REQUIRE(p.getSize() == 3);
+
+    REQUIRE(p.readUInt8() == 0);
+    REQUIRE(p.readUInt8() == 127);
+    REQUIRE(p.readUInt8() == 255);
+    REQUIRE_FALSE(p.hasData());
+}
+
+TEST_CASE("Packet write/read UInt16 round-trip", "[packet]") {
+    Packet p(1);
+    p.writeUInt16(0);
+    p.writeUInt16(0xBEEF);
+    p.writeUInt16(0xFFFF);
+    REQUIRE(p.getSize() == 6);
+
+    REQUIRE(p.readUInt16() == 0);
+    REQUIRE(p.readUInt16() == 0xBEEF);
+    REQUIRE(p.readUInt16() == 0xFFFF);
+}
+
+TEST_CASE("Packet write/read UInt32 round-trip", "[packet]") {
+    Packet p(1);
+    p.writeUInt32(0xDEADBEEF);
+    REQUIRE(p.readUInt32() == 0xDEADBEEF);
+}
+
+TEST_CASE("Packet write/read UInt64 round-trip", "[packet]") {
+    Packet p(1);
+    p.writeUInt64(0x0123456789ABCDEFULL);
+    REQUIRE(p.readUInt64() == 0x0123456789ABCDEFULL);
+}
+
+TEST_CASE("Packet write/read float round-trip", "[packet]") {
+    Packet p(1);
+    p.writeFloat(3.14f);
+    p.writeFloat(-0.0f);
+    p.writeFloat(1e10f);
+    REQUIRE(p.readFloat() == Catch::Approx(3.14f));
+    REQUIRE(p.readFloat() == -0.0f);
+    REQUIRE(p.readFloat() == Catch::Approx(1e10f));
+}
+
+TEST_CASE("Packet write/read string round-trip", "[packet]") {
+    Packet p(1);
+    p.writeString("Hello WoW");
+    p.writeString("");  // empty string
+    REQUIRE(p.readString() == "Hello WoW");
+    REQUIRE(p.readString() == "");
+}
+
+TEST_CASE("Packet writeBytes / readUInt8 array", "[packet]") {
+    Packet p(1);
+    const uint8_t buf[] = {0xAA, 0xBB, 0xCC};
+    p.writeBytes(buf, 3);
+    REQUIRE(p.getSize() == 3);
+    REQUIRE(p.readUInt8() == 0xAA);
+    REQUIRE(p.readUInt8() == 0xBB);
+    REQUIRE(p.readUInt8() == 0xCC);
+}
+
+TEST_CASE("Packet packed GUID round-trip", "[packet]") {
+    SECTION("Zero GUID") {
+        Packet p(1);
+        p.writePackedGuid(0);
+        REQUIRE(p.hasFullPackedGuid());
+        REQUIRE(p.readPackedGuid() == 0);
+    }
+
+    SECTION("Low GUID (single byte)") {
+        Packet p(1);
+        p.writePackedGuid(0x42);
+        REQUIRE(p.readPackedGuid() == 0x42);
+    }
+
+    SECTION("Full 64-bit GUID") {
+        Packet p(1);
+        uint64_t guid = 0x0102030405060708ULL;
+        p.writePackedGuid(guid);
+        REQUIRE(p.readPackedGuid() == guid);
+    }
+
+    SECTION("Max GUID") {
+        Packet p(1);
+        uint64_t guid = 0xFFFFFFFFFFFFFFFFULL;
+        p.writePackedGuid(guid);
+        REQUIRE(p.readPackedGuid() == guid);
+    }
+}
+
+TEST_CASE("Packet getRemainingSize and hasRemaining", "[packet]") {
+    Packet p(1);
+    p.writeUInt32(100);
+    p.writeUInt32(200);
+    REQUIRE(p.getRemainingSize() == 8);
+    REQUIRE(p.hasRemaining(8));
+    REQUIRE_FALSE(p.hasRemaining(9));
+
+    p.readUInt32();
+    REQUIRE(p.getRemainingSize() == 4);
+    REQUIRE(p.hasRemaining(4));
+    REQUIRE_FALSE(p.hasRemaining(5));
+
+    p.readUInt32();
+    REQUIRE(p.getRemainingSize() == 0);
+    REQUIRE(p.hasRemaining(0));
+    REQUIRE_FALSE(p.hasRemaining(1));
+}
+
+TEST_CASE("Packet setReadPos and skipAll", "[packet]") {
+    Packet p(1);
+    p.writeUInt8(10);
+    p.writeUInt8(20);
+    p.writeUInt8(30);
+
+    p.readUInt8(); // pos = 1
+    p.setReadPos(0);
+    REQUIRE(p.readUInt8() == 10);
+
+    p.skipAll();
+    REQUIRE(p.getRemainingSize() == 0);
+    REQUIRE_FALSE(p.hasData());
+}
+
+TEST_CASE("Packet constructed with data vector", "[packet]") {
+    std::vector<uint8_t> raw = {0x01, 0x02, 0x03};
+    Packet p(42, raw);
+    REQUIRE(p.getOpcode() == 42);
+    REQUIRE(p.getSize() == 3);
+    REQUIRE(p.readUInt8() == 0x01);
+}
+
+TEST_CASE("Packet constructed with rvalue data", "[packet]") {
+    Packet p(99, std::vector<uint8_t>{0xFF, 0xFE});
+    REQUIRE(p.getSize() == 2);
+    REQUIRE(p.readUInt8() == 0xFF);
+    REQUIRE(p.readUInt8() == 0xFE);
+}
+
+TEST_CASE("Packet mixed types interleaved", "[packet]") {
+    Packet p(1);
+    p.writeUInt8(0xAA);
+    p.writeUInt32(0xDEADBEEF);
+    p.writeString("test");
+    p.writeFloat(2.5f);
+    p.writeUInt16(0x1234);
+
+    REQUIRE(p.readUInt8() == 0xAA);
+    REQUIRE(p.readUInt32() == 0xDEADBEEF);
+    REQUIRE(p.readString() == "test");
+    REQUIRE(p.readFloat() == Catch::Approx(2.5f));
+    REQUIRE(p.readUInt16() == 0x1234);
+    REQUIRE_FALSE(p.hasData());
+}
+
+TEST_CASE("Packet hasFullPackedGuid returns false on empty", "[packet]") {
+    Packet p(1);
+    REQUIRE_FALSE(p.hasFullPackedGuid());
+}
+
+TEST_CASE("Packet getRemainingSize clamps after overshoot", "[packet]") {
+    Packet p(1);
+    p.writeUInt8(1);
+    p.setReadPos(999);
+    REQUIRE(p.getRemainingSize() == 0);
+    REQUIRE_FALSE(p.hasRemaining(1));
+}
diff --git a/tests/test_srp.cpp b/tests/test_srp.cpp
new file mode 100644
index 00000000..ad0b9550
--- /dev/null
+++ b/tests/test_srp.cpp
@@ -0,0 +1,127 @@
+// Phase 0 – SRP6a challenge/proof smoke tests
+#include <catch_amalgamated.hpp>
+#include "auth/srp.hpp"
+#include "auth/crypto.hpp"
+
+using wowee::auth::SRP;
+using wowee::auth::Crypto;
+
+// WoW 3.3.5a uses well-known SRP6a parameters.
+// Generator g = 7, N = a large 32-byte safe prime.
+// We use the canonical WoW values for integration-level tests.
+
+static const std::vector<uint8_t> kWoWGenerator = { 7 };
+
+// WoW's 32-byte large safe prime (little-endian)
+static const std::vector<uint8_t> kWoWPrime = {
+    0xB7, 0x9B, 0x3E, 0x2A, 0x87, 0x82, 0x3C, 0xAB,
+    0x8F, 0x5E, 0xBF, 0xBF, 0x8E, 0xB1, 0x01, 0x08,
+    0x53, 0x50, 0x06, 0x29, 0x8B, 0x5B, 0xAD, 0xBD,
+    0x5B, 0x53, 0xE1, 0x89, 0x5E, 0x64, 0x4B, 0x89
+};
+
+TEST_CASE("SRP initialize stores credentials", "[srp]") {
+    SRP srp;
+    // Should not throw
+    REQUIRE_NOTHROW(srp.initialize("TEST", "PASSWORD"));
+}
+
+TEST_CASE("SRP initializeWithHash accepts pre-computed hash", "[srp]") {
+    // Pre-compute SHA1("TEST:PASSWORD")
+    auto hash = Crypto::sha1(std::string("TEST:PASSWORD"));
+    REQUIRE(hash.size() == 20);
+
+    SRP srp;
+    REQUIRE_NOTHROW(srp.initializeWithHash("TEST", hash));
+}
+
+TEST_CASE("SRP feed produces A and M1 of correct sizes", "[srp]") {
+    SRP srp;
+    srp.initialize("TEST", "PASSWORD");
+
+    // Fabricate a server B (32 bytes, non-zero to avoid SRP abort)
+    std::vector<uint8_t> B(32, 0);
+    B[0] = 0x42; // Non-zero
+
+    std::vector<uint8_t> salt(32, 0xAA);
+
+    srp.feed(B, kWoWGenerator, kWoWPrime, salt);
+
+    auto A = srp.getA();
+    auto M1 = srp.getM1();
+    auto K = srp.getSessionKey();
+
+    // A should be 32 bytes (same size as N)
+    REQUIRE(A.size() == 32);
+    // M1 is SHA1 → 20 bytes
+    REQUIRE(M1.size() == 20);
+    // K is the interleaved session key → 40 bytes
+    REQUIRE(K.size() == 40);
+}
+
+TEST_CASE("SRP A is non-zero", "[srp]") {
+    SRP srp;
+    srp.initialize("PLAYER", "SECRET");
+
+    std::vector<uint8_t> B(32, 0);
+    B[3] = 0x01;
+    std::vector<uint8_t> salt(32, 0xBB);
+
+    srp.feed(B, kWoWGenerator, kWoWPrime, salt);
+
+    auto A = srp.getA();
+    bool allZero = true;
+    for (auto b : A) {
+        if (b != 0) { allZero = false; break; }
+    }
+    REQUIRE_FALSE(allZero);
+}
+
+TEST_CASE("SRP different passwords produce different M1", "[srp]") {
+    auto runSrp = [](const std::string& pass) {
+        SRP srp;
+        srp.initialize("TESTUSER", pass);
+        std::vector<uint8_t> B(32, 0);
+        B[0] = 0x11;
+        std::vector<uint8_t> salt(32, 0xCC);
+        srp.feed(B, kWoWGenerator, kWoWPrime, salt);
+        return srp.getM1();
+    };
+
+    auto m1a = runSrp("PASSWORD1");
+    auto m1b = runSrp("PASSWORD2");
+    REQUIRE(m1a != m1b);
+}
+
+TEST_CASE("SRP verifyServerProof rejects wrong proof", "[srp]") {
+    SRP srp;
+    srp.initialize("TEST", "PASSWORD");
+
+    std::vector<uint8_t> B(32, 0);
+    B[0] = 0x55;
+    std::vector<uint8_t> salt(32, 0xDD);
+
+    srp.feed(B, kWoWGenerator, kWoWPrime, salt);
+
+    // Random 20 bytes should not match the expected M2
+    std::vector<uint8_t> fakeM2(20, 0xFF);
+    REQUIRE_FALSE(srp.verifyServerProof(fakeM2));
+}
+
+TEST_CASE("SRP setUseHashedK changes behavior", "[srp]") {
+    auto runWithHashedK = [](bool useHashed) {
+        SRP srp;
+        srp.setUseHashedK(useHashed);
+        srp.initialize("TEST", "PASSWORD");
+        std::vector<uint8_t> B(32, 0);
+        B[0] = 0x22;
+        std::vector<uint8_t> salt(32, 0xEE);
+        srp.feed(B, kWoWGenerator, kWoWPrime, salt);
+        return srp.getM1();
+    };
+
+    auto m1_default = runWithHashedK(false);
+    auto m1_hashed = runWithHashedK(true);
+    // Different k derivation → different M1
+    REQUIRE(m1_default != m1_hashed);
+}