Add pytest-xdist regression test

- imported from PR #52, by Andrew Gilbert
- adapt xdist-versions supported for different pytest versions
- do not run xdist test for Python 3.10.1 due to an unrelated problem with that version

Author: mrbean-bremen

CHANGELOG.md

@@ -9,6 +9,8 @@
 - added automatic documentation build on change 
 - add Python 3.9, pypy3 and pytest 6.0 and 6.1 to CI builds
 - use GitHub Actions for builds, add Windows builds
+- add regression test for ``pytest-xdist`` 
+  (imported from [PR #52](https://github.com/ftobia/pytest-ordering/pull/52))
 
 ## [Version 0.7.1](https://pypi.org/project/pytest-order/0.7.1/)
 Update after renaming the repository and the package.

tests/test_xdist_handling.py

@@ -0,0 +1,69 @@
+# -*- coding: utf-8 -*-
+
+import pytest
+import pytest_order
+
+pytest_plugins = ['pytester']
+
+
+@pytest.mark.skipif(pytest.__version__ == "3.10.1",
+                    reason="That version seems to have a parser problem")
+def test_xdist_ordering(tmpdir):
+    testname = str(tmpdir.join("first_test.py"))
+    with open(testname, "w") as fi:
+        fi.write(
+            """
+import pytest
+
+val = 1
+
+@pytest.mark.order("second")
+def test_second_integer():
+    global val
+    assert val == 2
+    val += 1
+
+def test_last_integer():
+    assert val == 3
+
+@pytest.mark.order("first")
+def test_first_integer():
+    global val
+    assert val == 1
+    val += 1
+"""
+        )
+
+    testname = str(tmpdir.join("second_test.py"))
+    with open(testname, "w") as fi:
+        fi.write(
+            """
+import pytest
+
+val = "frog"
+
+@pytest.mark.order("second")
+def test_second_string():
+    global val
+    assert val == "goat"
+    val = "fish"
+
+def test_last_string():
+    assert val == "fish"
+
+@pytest.mark.order("first")
+def test_first_string():
+    global val
+    assert val == "frog"
+    val = "goat"
+"""
+        )
+    # With `loadfile`, the tests should pass
+    args = ["-n3", "--dist=loadfile", str(tmpdir)]
+    ret = pytest.main(args, [pytest_order])
+    assert ret == 0
+
+    # Without `loadfile`, the tests should fail
+    args = ["-n3", str(tmpdir)]
+    ret = pytest.main(args, [pytest_order])
+    assert ret == 1

tox.ini

@@ -26,6 +26,10 @@ deps =
     pytest61: pytest>=6.1,<6.2
     pytest{40,41,42}: attrs<19.2
     pytest-cov<2.10
+    pytest{36}: pytest-forked<1.3.0
+    pytest{36,37,38,39,40,41,42,43}: pytest-xdist<1.28.0
+    pytest{44,45,46,50,51,52,53,54}: pytest-xdist<2.0.0
+    pytest{60,61}: pytest-xdist
 
 commands =
     coverage run --source=pytest_order -m pytest tests