Remove $PYTEST_ADDOPTS with newer pytest

Since 953a3f0 options are parsed already, e.g. "-v" from
`$PYTEST_ADDOPTS`, and therefore `$PYTEST_ADDOPTS` should be unset for
child processes.

Author: blueyed

src/xdist/remote.py

@@ -243,6 +243,8 @@ def setup_config(config, basetemp):
 
     if hasattr(Config, "InvocationParams"):
         config = _prepareconfig(args, None)
+        if "PYTEST_ADDOPTS" in os.environ:
+            del os.environ["PYTEST_ADDOPTS"]
     else:
         config = remote_initconfig(option_dict, args)
         config.args = args

testing/acceptance_test.py

@@ -559,7 +559,7 @@ def test_hello(myarg):
     assert result.ret
 
 
-def test_config_initialization(testdir, pytestconfig):
+def test_config_initialization(testdir, monkeypatch, pytestconfig):
     """Ensure workers and master are initialized consistently. Integration test for #445"""
     if not hasattr(pytestconfig, "invocation_params"):
         pytest.skip(
@@ -568,7 +568,8 @@ def test_config_initialization(testdir, pytestconfig):
     testdir.makepyfile(
         **{
             "dir_a/test_foo.py": """
-                def test_1(): pass
+                def test_1(request):
+                    assert request.config.verbose == 1
         """
         }
     )
@@ -579,6 +580,7 @@ def test_1(): pass
         testpaths=dir_a
     """,
     )
+    monkeypatch.setenv("PYTEST_ADDOPTS", "-v")
     result = testdir.runpytest("-n2", "-c", "myconfig.ini", "-v")
     result.stdout.fnmatch_lines(["dir_a/test_foo.py::test_1*"])