Fix pytest without cache -pno:cacheprovider (#29)

pytest_ruff/_pytest_compat.py

@@ -6,7 +6,7 @@
 import pytest
 
 try:
-    from pytest import Stash, StashKey
+    from pytest import Stash as Stash, StashKey
 except ImportError:
     import _pytest.store
 
@@ -36,10 +36,7 @@ def get_stash_object(config):
 
 
 def get_stash(config):
-    missing = object()
-    stash = get_stash_object(config).get(_MTIMES_STASH_KEY, default=missing)
-    assert stash is not missing
-    return stash
+    return get_stash_object(config).get(_MTIMES_STASH_KEY, default=None)
 
 
 def set_stash(config, value):

tests/test_plugin.py

@@ -88,11 +88,29 @@ def test_broken_ruff_config():
             "-m",
             "pytest",
             "--ruff",
-            "tests/assets/broken_config/empty.py",
+            "tests/assets/config_broken/empty.py",
         ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
     )
     out, err = process.communicate()
     assert err.decode() == ""
     assert "unknown field `broken`" in out.decode()
+
+
+def test_without_pytest_cache():
+    process = subprocess.Popen(
+        [
+            sys.executable,
+            "-m",
+            "pytest",
+            "--ruff",
+            "-pno:cacheprovider",
+            "tests/assets/ok.py",
+        ],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+    )
+    out, err = process.communicate()
+    assert err.decode() == ""
+    assert "tests/assets/ok.py ." in out.decode()

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 isolated_build = true
-envlist = py{38,39,310,311,312}-pytest{5,6,7,8,810,81},lint
+envlist = py{38,39,310,311,312}-pytest{5,6,7,8,810,latest},lint
 
 [testenv]
 allowlist_externals = poetry
@@ -9,10 +9,10 @@ commands =
     pytest5: pip install "pytest<6"
     pytest6: pip install "pytest>=6,<7"
     pytest7: pip install "pytest>=7,<8"
-    pytest8: pip install "pytest>=8,<8.1"
+    pytest8: pip install "pytest>=8,<9"
     # pytest 8.1.0 was yanked, but their "broken behaviour" will comeback soon
     pytest810: pip install "pytest==8.1.0"
-    pytest81: pip install "pytest>=8.1,<9"
+    pytestlatest: pip install pytest
     # Disable ruff plugin to generate better coverage results
     poetry run pytest -p no:ruff -vvv --cov --cov-append --cov-report term --cov-report xml {posargs}