Add PyPI/coverage/test badges, enable code coverage in CI

- Add shields.io badges (PyPI, Python versions, tests, coverage, license)
- Add pytest-cov and Codecov upload to test workflow
- Coverage uploads on Python 3.13 only to avoid duplicates

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 0xC000005

.github/workflows/test.yml

@@ -27,4 +27,10 @@ jobs:
         run: uv sync --python ${{ matrix.python-version }}
 
       - name: Run tests
-        run: uv run pytest tests/ -v
+        run: uv run pytest tests/ -v --cov=pychebyshev --cov-report=xml
+
+      - name: Upload coverage to Codecov
+        if: matrix.python-version == '3.13'
+        uses: codecov/codecov-action@v5
+        with:
+          files: coverage.xml

README.md

@@ -1,5 +1,11 @@
 # PyChebyshev
 
+[![PyPI version](https://img.shields.io/pypi/v/pychebyshev)](https://pypi.org/project/pychebyshev/)
+[![Python versions](https://img.shields.io/pypi/pyversions/pychebyshev)](https://pypi.org/project/pychebyshev/)
+[![Tests](https://github.com/0xC000005/PyChebyshev/actions/workflows/test.yml/badge.svg)](https://github.com/0xC000005/PyChebyshev/actions/workflows/test.yml)
+[![codecov](https://codecov.io/gh/0xC000005/PyChebyshev/graph/badge.svg)](https://codecov.io/gh/0xC000005/PyChebyshev)
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
+
 **A standalone Python implementation of multi-dimensional Chebyshev tensor interpolation**
 
 This project provides an **extremely short, standalone Python implementation** (although not fully optimized, without getting tedious) of the Chebyshev tensor method, **for educational purposes only**, demonstrating that it achieves **comparable accuracy to the state-of-the-art MoCaX library** for European option pricing via Black-Scholes.

pyproject.toml

@@ -67,4 +67,5 @@ dev = [
     "mkdocs-material>=9.7.1",
     "mkdocstrings[python]>=1.0.3",
     "pytest>=8.4.2",
+    "pytest-cov>=7.0.0",
 ]