feat(zig): add parallel test runner for 7x faster CI

- Create run-all-tests.sh with xargs-based parallel execution
- Add --fast (default), --all, --slow modes to control test selection
- Exclude slow tests (fuzz, stress, large-data) by default
- 39 fast tests complete in ~19s vs ~200s+ sequential
- Add Makefile targets: test-parity-parallel, test-parity-all, test-slow

Closes TASK-140

Author: subtleGradient

.tasks/backlog/TASK-140-parallel-test-runner.md

@@ -21,14 +21,14 @@ Implement a parallel test runner to speed up CI and local development feedback l
 
 ## Acceptance Criteria
 
-1. [ ] Create `run-all-tests.sh` that runs tests in parallel
-2. [ ] Use GNU parallel or xargs -P for parallelism
-3. [ ] Collect and summarize results at end
-4. [ ] Exit non-zero if any test fails
-5. [ ] Support `--jobs N` or `PARALLEL_JOBS` env var
-6. [ ] Default to `nproc` or 4 concurrent jobs
-7. [ ] Show progress (e.g., "12/40 tests completed")
-8. [ ] Preserve individual test output for debugging failures
+1. [x] Create `run-all-tests.sh` that runs tests in parallel
+2. [x] Use GNU parallel or xargs -P for parallelism
+3. [x] Collect and summarize results at end
+4. [x] Exit non-zero if any test fails
+5. [x] Support `--jobs N` or `PARALLEL_JOBS` env var
+6. [x] Default to `nproc` or 4 concurrent jobs
+7. [x] Show progress (e.g., "12/40 tests completed")
+8. [x] Preserve individual test output for debugging failures
 
 ## Implementation Options
 
@@ -94,7 +94,31 @@ With 40 tests at ~5 seconds each:
 ## Progress Log
 
 - 2024-12-20: Created task card
+- 2024-12-20: Implemented parallel test runner
 
 ## Completion Notes
 
-(To be filled upon completion)
+Completed on 2024-12-20.
+
+### Implementation
+
+Created `zig/harness/run-all-tests.sh` with:
+- Parallel execution using xargs -P (portable, no GNU parallel dependency)
+- `--fast` mode (default): excludes slow tests (fuzz, stress, large-data)
+- `--all` mode: runs all tests including slow ones
+- `--slow` mode: runs only slow tests
+- `--jobs N` / `PARALLEL_JOBS` env var for parallelism control
+- `--sequential` for debugging
+- Progress output and summary with pass/fail/skip counts
+- Individual test logs preserved in `.tmp/test-results/`
+
+Added Makefile targets:
+- `test-parity-parallel`: Fast tests only (default)
+- `test-parity-all`: All tests including slow ones
+- `test-slow`: Only slow tests
+
+### Results
+
+- **39 fast tests** complete in ~19s with 10 parallel jobs (vs ~200s+ sequential)
+- **7x+ speedup** for regular CI runs
+- Slow tests (fuzz, stress, large-data) excluded by default but available via `--all`

zig/Makefile

@@ -9,7 +9,7 @@
 #   make clean        - Clean build artifacts
 #   make help         - Show this help
 
-.PHONY: all test test-unit test-parity test-browser build clean help \
+.PHONY: all test test-unit test-parity test-parity-parallel test-parity-all test-slow test-browser build clean help \
         _test-unit _test-parity _test-browser dist \
         universal build-arm64 build-x64 size-report
 
@@ -70,6 +70,38 @@ test-parity:
 	@echo ""
 	@cd harness && bash test-parity.sh
 
+# Shell parity tests (parallel execution for faster CI)
+# Uses run-all-tests.sh to run all test-*.sh scripts concurrently
+# Default: uses nproc jobs. Override with PARALLEL_JOBS env var.
+# Note: Excludes slow tests by default (fuzz, stress, large-data).
+test-parity-parallel: build
+	@echo ""
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo "$(CYAN)$(BOLD)  Shell Parity Tests (Parallel - Fast)$(RESET)"
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo ""
+	@cd harness && bash run-all-tests.sh --fast
+
+# Shell parity tests including slow tests (fuzz, stress, large-data)
+# Use this for thorough CI runs or release validation.
+test-parity-all: build
+	@echo ""
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo "$(CYAN)$(BOLD)  Shell Parity Tests (Parallel - All)$(RESET)"
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo ""
+	@cd harness && bash run-all-tests.sh --all
+
+# Only slow tests (fuzz, stress, large-data)
+# Use for extended testing or CI nightly builds.
+test-slow: build
+	@echo ""
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo "$(CYAN)$(BOLD)  Slow Tests Only (Fuzz, Stress, Large-Data)$(RESET)"
+	@echo "$(CYAN)$(BOLD)════════════════════════════════════════════════════════════════$(RESET)"
+	@echo ""
+	@cd harness && bash run-all-tests.sh --slow
+
 # Browser tests (Playwright + sql.js)
 test-browser:
 	@echo ""
@@ -277,10 +309,13 @@ help:
 	@echo "$(BOLD)Zig CR-SQLite Makefile$(RESET)"
 	@echo ""
 	@echo "$(BOLD)Test Targets:$(RESET)"
-	@echo "  $(CYAN)make test$(RESET)         - Run all tests concurrently (unit + parity + browser)"
-	@echo "  $(CYAN)make test-unit$(RESET)    - Run Zig unit tests only"
-	@echo "  $(CYAN)make test-parity$(RESET)  - Run shell parity tests only"
-	@echo "  $(CYAN)make test-browser$(RESET) - Run Playwright browser tests only"
+	@echo "  $(CYAN)make test$(RESET)                - Run all tests concurrently (unit + parity + browser)"
+	@echo "  $(CYAN)make test-unit$(RESET)           - Run Zig unit tests only"
+	@echo "  $(CYAN)make test-parity$(RESET)         - Run shell parity tests only (sequential)"
+	@echo "  $(CYAN)make test-parity-parallel$(RESET) - Run shell parity tests (parallel, excludes slow)"
+	@echo "  $(CYAN)make test-parity-all$(RESET)     - Run ALL shell parity tests (including slow)"
+	@echo "  $(CYAN)make test-slow$(RESET)           - Run only slow tests (fuzz, stress, large-data)"
+	@echo "  $(CYAN)make test-browser$(RESET)        - Run Playwright browser tests only"
 	@echo ""
 	@echo "$(BOLD)Build Targets:$(RESET)"
 	@echo "  $(CYAN)make build$(RESET)        - Build the Zig extension"