The test_readline stalls for an unknown reason on OpenIndiana as of March 7th, 2021
with readline-6.3. So we skip this test for now.

--- Python-3.9.2/Lib/test/test_readline.py.orig	2021-02-19 13:31:44.000000000 +0000
+++ Python-3.9.2/Lib/test/test_readline.py	2021-03-07 15:58:51.393990143 +0000
@@ -33,6 +33,8 @@
             print(f"readline library version: {readline._READLINE_LIBRARY_VERSION!r}")
         print(f"use libedit emulation? {is_editline}")
 
+if sys.platform.startswith("sunos"):
+    raise unittest.SkipTest("test doesn't work well on OpenIndiana with readline-6.3")
 
 @unittest.skipUnless(hasattr(readline, "clear_history"),
                      "The history update test cannot be run because the "