Handle os.chdir() during collection

src/_pytest/config/__init__.py

@@ -603,6 +603,7 @@ class Config(object):
         self._warn = self.pluginmanager._warn
         self.pluginmanager.register(self, "pytestconfig")
         self._configured = False
+        self.cwd = os.getcwd()
 
         def do_setns(dic):
             import pytest
@@ -847,11 +848,10 @@ class Config(object):
                 args, self.option, namespace=self.option
             )
             if not args:
-                cwd = os.getcwd()
-                if cwd == self.rootdir:
+                if self.cwd == self.rootdir:
                     args = self.getini("testpaths")
                 if not args:
-                    args = [cwd]
+                    args = [self.cwd]
             self.args = args
         except PrintHelp:
             pass