CI dummpy dependencies

.github/workflows/ci.yml

@@ -10,6 +10,13 @@ jobs:
     - uses: actions/setup-python@v5
       with:
         python-version: '3.11'
+    - name: Dummy dependencies
+      run: |
+        python3 _pip_install_dummy.py PyGObject 3.99
+        python3 _pip_install_dummy.py pySerial 3.5
+        python3 _pip_install_dummy.py Pillow 7.1
+        python3 _pip_install_dummy.py scour 0.37
+        python3 _pip_install_dummy.py tinycss2 1.0
     - run: pip install -r requirements.txt pytest
     - name: Test
       run: |

_pip_install_dummy.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+"""
+Create a dummy Python package and install it with pip.
+"""
+
+import sys
+import subprocess
+import tempfile
+from pathlib import Path
+
+name, version = sys.argv[1:]
+
+pyprojectbody = f"""[project]
+name = "{name}"
+version = "{version}"
+"""
+
+with tempfile.TemporaryDirectory() as tmpdirname:
+    assert isinstance(tmpdirname, str)
+    pyprojectpath = Path(tmpdirname) / "pyproject.toml"
+    pyprojectpath.write_text(pyprojectbody)
+    subprocess.check_call([sys.executable, "-m", "pip", "install", tmpdirname])