diff --git a/.github/workflows/codespell.yml b/.github/workflows/codespell.yml
index 45fc51e80..1d9616fcc 100644
--- a/.github/workflows/codespell.yml
+++ b/.github/workflows/codespell.yml
@@ -3,9 +3,9 @@ name: Codespell
 
 on:
   push:
-    branches: [milgram]
+    branches: [nightingale]
   pull_request:
-    branches: [milgram]
+    branches: [nightingale]
 
 permissions:
   contents: read
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
new file mode 100644
index 000000000..421e75984
--- /dev/null
+++ b/.github/workflows/tests.yml
@@ -0,0 +1,67 @@
+name: Tests
+
+on:
+  push:
+    branches: [nightingale]
+  pull_request:
+    branches: [nightingale]
+
+# Cancel superseded runs on the same ref to save runner minutes.
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: pytest (${{ matrix.os }}, py${{ matrix.python-version }})
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 15
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        python-version: ["3.10", "3.13"]
+
+    env:
+      QT_QPA_PLATFORM: offscreen
+      SDL_VIDEODRIVER: dummy
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+
+      # PyQt6 wheels need EGL/GL system libraries on headless Linux runners.
+      # Runner DNS intermittently fails for *.ubuntu.com, so apt sources
+      # are repointed to mirrors.kernel.org before updating/installing.
+      - name: Install Qt system dependencies (Linux)
+        if: runner.os == 'Linux'
+        run: |
+          . /etc/os-release
+          sudo mv /etc/apt/sources.list.d/*.sources /etc/apt/sources.list.d/*.list /tmp/ 2>/dev/null || true
+          sudo rm -f /etc/apt/sources.list
+          for pocket in "" -updates -security; do
+            echo "deb https://mirrors.kernel.org/ubuntu $VERSION_CODENAME$pocket main restricted universe multiverse" | sudo tee -a /etc/apt/sources.list
+          done
+          for attempt in 1 2 3; do
+            if sudo apt-get update && sudo apt-get install -y --no-install-recommends \
+              libegl1 libgl1 libxkbcommon0 libdbus-1-3 libfontconfig1; then
+              exit 0
+            fi
+            echo "apt attempt $attempt failed; retrying in 15s..."
+            sleep 15
+          done
+          exit 1
+
+      # conftest.py puts the repo root on sys.path, so tests exercise the
+      # source tree; opensesame-core provides the third-party dependencies.
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install opensesame-core pytest pygame imageio imageio-ffmpeg
+
+      - name: Run tests
+        run: python -m pytest tests/ -q
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 000000000..1e79a571f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,121 @@
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# Virtual environments
+.venv/
+venv/
+env/
+ENV/
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# PyInstaller
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# pyenv
+.python-version
+
+# pipenv
+Pipfile.lock
+
+# UV
+uv.lock
+
+# poetry
+poetry.lock
+
+# macOS
+.DS_Store
+.AppleDouble
+.LSOverride
+Icon?
+._*
+.Spotlight-V100
+.Trashes
+
+# Windows
+Thumbs.db
+ehthumbs.db
+Desktop.ini
+$RECYCLE.BIN/
+
+# Linux
+*~
+.fuse_hidden*
+
+# Editor / IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+.project
+.pydevproject
+.settings/
+
+# OpenSesame test artifacts (tests drop outputs in the repo root)
+/tmp.osexp
+/test_*.png
+/test_*.csv
+/test_*.xlsx