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 self.cwd == self.rootdir:
-                if cwd == self.rootdir:
                     args = self.getini("testpaths")
                 if not args:
-                    args = [cwd]
+                    args = [self.cwd]
             self.args = args
         except PrintHelp:
             pass

testing/test_collection.py

@@ -1017,5 +1017,29 @@ def test_collect_handles_raising_on_dunder_class(testdir):
     """
     )
     result = testdir.runpytest()
-    assert result.ret == 0
     result.stdout.fnmatch_lines(["*1 passed in*"])
+    assert result.ret == 0
+
+
+def test_collect_with_chdir_during_import(testdir):
+    subdir = testdir.tmpdir.mkdir("sub")
+    testdir.tmpdir.join("conftest.py").write(
+        textwrap.dedent(
+            """
+            import os
+            os.chdir(%r)
+            """
+            % (str(subdir),)
+        )
+    )
+    testdir.makepyfile(
+        """
+        def test_1():
+            import os
+            assert os.getcwd() == %r
+        """
+        % (str(subdir),)
+    )
+    result = testdir.runpytest()
+    result.stdout.fnmatch_lines(["*1 passed in*"])
+    assert result.ret == 0