Quick fix for tests in config depended on the current directory

When running those tests from pytest's root folder, they would
fail because they would end up picking pytest's own pytest.ini

testing/test_config.py

@@ -592,6 +592,7 @@ class TestRootdir:
         assert inicfg == {}
 
     def test_nothing(self, tmpdir):
+        tmpdir.chdir()
         rootdir, inifile, inicfg = determine_setup(None, [tmpdir])
         assert rootdir == tmpdir
         assert inifile is None
@@ -603,6 +604,7 @@ class TestRootdir:
         assert rootdir == tmpdir
 
     def test_with_arg_outside_cwd_without_inifile(self, tmpdir):
+        tmpdir.chdir()
         a = tmpdir.mkdir("a")
         b = tmpdir.mkdir("b")
         rootdir, inifile, inicfg = determine_setup(None, [a, b])