Add test coverage reporting and README badges

- Update CI workflow to generate coverage reports with pytest-cov
- Upload coverage to Codecov for tracking
- Add test status and coverage badges to README
- Add `make test-cov` target for local coverage reports
- Update .gitignore to exclude coverage files

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: ChanceSiyuan

.github/workflows/test.yml

@@ -27,5 +27,13 @@ jobs:
     - name: Install dependencies
       run: uv sync --dev
 
-    - name: Run tests
-      run: uv run pytest --verbose
+    - name: Run tests with coverage
+      run: uv run pytest --verbose --cov=bpdecoderplus --cov-report=xml --cov-report=term
+
+    - name: Upload coverage to Codecov
+      uses: codecov/codecov-action@v4
+      with:
+        file: ./coverage.xml
+        flags: unittests
+        name: codecov-umbrella
+        fail_ci_if_error: false

.gitignore

@@ -23,6 +23,7 @@ build/
 *.egg
 .pytest_cache/
 .coverage
+coverage.xml
 htmlcov/
 .uv/
 uv.lock

Makefile

@@ -1,11 +1,12 @@
-.PHONY: help install setup test generate-dataset clean
+.PHONY: help install setup test test-cov generate-dataset clean
 
 help:
 	@echo "Available targets:"
 	@echo "  install          - Install uv package manager"
 	@echo "  setup            - Set up development environment with uv"
 	@echo "  generate-dataset - Generate noisy circuit dataset"
 	@echo "  test             - Run tests"
+	@echo "  test-cov         - Run tests with coverage report"
 	@echo "  clean            - Remove generated files and caches"
 
 install:
@@ -23,8 +24,14 @@ generate-dataset:
 test:
 	uv run pytest
 
+test-cov:
+	uv run pytest --cov=bpdecoderplus --cov-report=html --cov-report=term
+
 clean:
 	rm -rf .pytest_cache
 	rm -rf __pycache__
+	rm -rf htmlcov
+	rm -rf .coverage
+	rm -rf coverage.xml
 	find . -type d -name "__pycache__" -exec rm -rf {} + 2>/dev/null || true
 	find . -type f -name "*.pyc" -delete

README.md

@@ -1,5 +1,8 @@
 # BPDecoderPlus: Quantum Error Correction with Belief Propagation
 
+[![Tests](https://github.com/GiggleLiu/BPDecoderPlus/actions/workflows/test.yml/badge.svg)](https://github.com/GiggleLiu/BPDecoderPlus/actions/workflows/test.yml)
+[![codecov](https://codecov.io/gh/GiggleLiu/BPDecoderPlus/branch/main/graph/badge.svg)](https://codecov.io/gh/GiggleLiu/BPDecoderPlus)
+
 A winter school project on circuit-level decoding of surface codes using belief propagation and integer programming decoders, with extensions for atom loss in neutral atom quantum computers.
 
 ## Project Goals