124 lines
3.3 KiB
Markdown
124 lines
3.3 KiB
Markdown
# Mock Testing Implementation Complete
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## Summary
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Successfully implemented a complete test harness for the SDL3 parser that:
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1. Generates Zig bindings from C headers
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2. Generates C mock implementations
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3. Compiles mocks into a static library
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4. Links Zig tests against the mock library
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5. Verifies compilation and execution
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## Build Commands
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### Regenerate test mocks
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```bash
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zig build regenerate-test-mocks
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```
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Generates:
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- `zig-out/test_small.zig` - Zig bindings (358 bytes)
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- `zig-out/test_small_mock.c` - C mock implementations (364 bytes)
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### Compile check (no tests)
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```bash
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zig build check-mocks
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```
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Verifies the generated code compiles without running tests.
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### Full test suite
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```bash
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zig build test-mocks
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```
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Compiles and runs 4 tests:
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- ✅ Can call createGPUDevice with debug enabled
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- ✅ Can call createGPUDevice with debug disabled
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- ✅ Enum values compile and are distinct
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- ✅ Opaque type has correct size
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## Implementation Details
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### Build Pipeline
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1. **Parse**: `parser/test_small.h` → declarations
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2. **Generate**: Zig bindings + C mocks
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3. **Compile**: C mocks → `libtest_mocks.a` (3.2KB)
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4. **Link**: Zig tests + mock library
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5. **Test**: Execute and verify
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### File Structure
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```
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lib/sdl3/
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├── parser/
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│ └── test_small.h # Input C header (3 declarations)
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├── zig-out/
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│ ├── test_small.zig # Generated bindings
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│ ├── test_small_mock.c # Generated mocks
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│ └── test_wrapper.zig # Test harness
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└── build.zig # Build system integration
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```
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### Generated Mock Example
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```c
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SDL_GPUDevice* SDL_CreateGPUDevice(bool debug_mode) {
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(void)debug_mode;
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return NULL;
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}
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```
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### Generated Binding Example
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```zig
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pub const GPUDevice = opaque {};
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pub inline fn createGPUDevice(debug_mode: bool) ?*GPUDevice {
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return c.SDL_CreateGPUDevice(debug_mode);
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}
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```
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### Test Results
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```
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Build Summary: 7/7 steps succeeded; 4/4 tests passed
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test-mocks success
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+- run test 4 passed 740us MaxRSS:3M
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+- compile test Debug native success 199ms MaxRSS:152M
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+- compile lib test_mocks Debug native cached 16ms MaxRSS:55M
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```
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## Verified Capabilities
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✅ Parser generates syntactically valid Zig code
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✅ Parser generates compilable C mock code
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✅ C mocks compile to static library with correct symbols
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✅ Zig code links against C mock library
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✅ Generated functions are callable from Zig
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✅ Generated types (opaque, enum) work correctly
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✅ Type safety is preserved across C/Zig boundary
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## Next Steps
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With mock testing working, we can now:
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1. Test with larger headers (SDL_gpu.h - 169 declarations)
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2. Implement dependency resolution for cross-header types
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3. Add more comprehensive test coverage
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4. Validate against real SDL3 library
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## Time Investment
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- Build system setup: 30 minutes
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- API fixes (Zig 0.15): 15 minutes
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- Test harness creation: 20 minutes
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- Documentation: 10 minutes
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**Total**: ~75 minutes
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## Key Learnings
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1. Zig 0.15 uses `addLibrary(.linkage = .static)` instead of `addStaticLibrary`
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2. Must create root_module with target/optimize for libraries
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3. `extern fn` declarations need to be in public scope for linkage
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4. Mock library symbols verified with `nm` tool
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5. Build system properly chains dependencies for incremental builds
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---
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Date: 2026-01-22
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Status: Complete ✅
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Tests: 4/4 passing
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