ci: add multi-Python test matrix and coverage reporting

- Split CI into lint and test jobs for faster feedback
- Add Python 3.10, 3.11, 3.12, 3.13 test matrix with fail-fast: false
- Add pytest-cov to dev dependencies
- Add coverage threshold enforcement (85%) in CI
- Add 'make coverage' target for local coverage reporting

Author: zurfjereluhmie

.github/workflows/ci.yml

@@ -7,8 +7,8 @@ on:
     branches: [main]
 
 jobs:
-  ci:
-    name: Lint, typecheck & test
+  lint:
+    name: Lint, format & typecheck
     runs-on: ubuntu-latest
 
     steps:
@@ -36,5 +36,29 @@ jobs:
       - name: Typecheck (ty)
         run: uv run ty check
 
-      - name: Test (pytest)
-        run: uv run pytest tests/ -q
+  test:
+    name: Test (Python ${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v7
+        with:
+          enable-cache: true
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: uv sync --group dev
+
+      - name: Test with coverage
+        run: uv run pytest tests/ -q --cov=evalwire --cov-report=term-missing --cov-fail-under=85

Makefile

@@ -1,6 +1,6 @@
 .DEFAULT_GOAL := help
 
-.PHONY: help install install-dev install-demo sync lint format typecheck test check fix pre-commit docs docs-serve clean
+.PHONY: help install install-dev install-demo sync lint format typecheck test coverage check fix pre-commit docs docs-serve clean
 
 help: ## Show this help message
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) \
@@ -30,6 +30,9 @@ typecheck: ## Run ty type checker
 test: ## Run pytest
 	uv run pytest tests/ -q
 
+coverage: ## Run pytest with coverage report
+	uv run pytest tests/ -q --cov=evalwire --cov-report=term-missing --cov-fail-under=85
+
 check: lint format typecheck test ## Run all checks (lint, format, typecheck, test)
 
 fix: ## Auto-fix lint and format issues

pyproject.toml

@@ -50,6 +50,7 @@ dev = [
     "pre-commit>=4.5.1",
     "pytest>=8.0",
     "pytest-asyncio>=0.23",
+    "pytest-cov>=6.0",
     "pytest-mock>=3.14",
     "ruff>=0.15.8",
     "ty>=0.0.26",