fix[test]: clean-up docker images in test_*linux*_only.py

We are reaching disk space limits (14 GB) when running tests.
Add a fixture to clean-up docker images after tests.
This fixture is applied on tests that pull a specific image for one test only in order not to take too much time pulling that image many times.

test/conftest.py

@@ -1,7 +1,15 @@
 from __future__ import annotations
 
+import json
+import subprocess
+from typing import Generator
+
 import pytest
 
+from cibuildwheel.util import detect_ci_provider
+
+from .utils import platform
+
 
 def pytest_addoption(parser) -> None:
     parser.addoption(
@@ -21,3 +29,29 @@ def pytest_addoption(parser) -> None:
 )
 def build_frontend_env(request) -> dict[str, str]:
     return request.param  # type: ignore[no-any-return]
+
+
+@pytest.fixture()
+def docker_cleanup() -> Generator[None, None, None]:
+    def get_images() -> set[str]:
+        images = subprocess.run(
+            ["docker", "image", "ls", "--format", "{{json .ID}}"],
+            text=True,
+            check=True,
+            stdout=subprocess.PIPE,
+        ).stdout
+        return {json.loads(image.strip()) for image in images.splitlines() if image.strip()}
+
+    if detect_ci_provider() is None or platform != "linux":
+        try:
+            yield
+        finally:
+            pass
+        return
+    images_before = get_images()
+    try:
+        yield
+    finally:
+        images_after = get_images()
+        for image in images_after - images_before:
+            subprocess.run(["docker", "rmi", image], check=False)

test/test_container_images.py

@@ -23,6 +23,7 @@
 )
 
 
+@pytest.mark.usefixtures("docker_cleanup")
 def test(tmp_path):
     if utils.platform != "linux":
         pytest.skip("the test is only relevant to the linux build")

test/test_manylinuxXXXX_only.py

@@ -53,6 +53,7 @@
     "manylinux_image",
     ["manylinux1", "manylinux2010", "manylinux2014", "manylinux_2_24", "manylinux_2_28"],
 )
+@pytest.mark.usefixtures("docker_cleanup")
 def test(manylinux_image, tmp_path):
     if utils.platform != "linux":
         pytest.skip("the container image test is only relevant to the linux build")

test/test_musllinux_X_Y_only.py

@@ -28,6 +28,7 @@
     "musllinux_image",
     ["musllinux_1_1", "musllinux_1_2"],
 )
+@pytest.mark.usefixtures("docker_cleanup")
 def test(musllinux_image, tmp_path):
     if utils.platform != "linux":
         pytest.skip("the container image test is only relevant to the linux build")