Update test

Author: WardBrian

test/__init__.py

@@ -5,6 +5,7 @@
 import sys
 import unittest
 from importlib import reload
+from io import StringIO
 
 
 class CustomTestCase(unittest.TestCase):
@@ -32,10 +33,11 @@ def without_import(self, library, module):
             yield
         reload(module)
 
+    # recipe modified from https://stackoverflow.com/a/36491341
     @contextlib.contextmanager
-    def replace_stdin(self, target):
+    def replace_stdin(self, target: str):
         orig = sys.stdin
-        sys.stdin = target
+        sys.stdin = StringIO(target)
         yield
         sys.stdin = orig
 

test/test_utils.py

@@ -866,7 +866,7 @@ def test_bad_version(self):
 
     def test_interactive_extra_args(self):
         with LogCapture() as log:
-            with self.replace_stdin(io.StringIO("9.99.9\n")):
+            with self.replace_stdin("9.99.9\n"):
                 res = install_cmdstan(version="2.29.2", interactive=True)
         log.check_present(
             (