ci: Test on Python 3.13 (nightly) (#873)

* ci: Test on Python 3.13 (nightly)

* Force Nox Python version

* Allow sdist for `coverage`

.github/workflows/tests.yml

@@ -49,6 +49,7 @@ jobs:
       LS_PORT: "8080"
       NOXSESSION: "${{ matrix.session }}"
       NOXPYTHON: "${{ matrix.python-version }}"
+      NOXFORCEPYTHON: "${{ matrix.python-version }}"
     strategy:
       fail-fast: false
       matrix:
@@ -67,6 +68,12 @@ jobs:
           experimental: true
           nightly: true
 
+        - python-version: "3.13"
+          os: "ubuntu-latest"
+          session: "tests"
+          experimental: true
+          nightly: true
+
         - python-version: "3.11"
           os: "windows-latest"
           session: "tests"

noxfile.py

@@ -42,6 +42,9 @@ def tests(session: Session) -> None:
     if GH_ACTIONS_ENV_VAR in os.environ:
         deps.append("pytest-github-actions-annotate-failures")
 
+    if session.python == "3.13":
+        env["PIP_NO_BINARY"] = "coverage"
+
     session.install(".", env=env)
     session.install(*deps, env=env)
     args = session.posargs or ["-m", "not integration_test"]