diff --git a/rubygem-minitest.spec b/rubygem-minitest.spec
index 432f1da..7b912b7 100644
--- a/rubygem-minitest.spec
+++ b/rubygem-minitest.spec
@@ -68,6 +68,11 @@ rm -rf %{buildroot}
 
 %check
 pushd .%{geminstdir}
+
+# spec test suite is unstable.
+# https://github.com/seattlerb/minitest/issues/257
+mv test/minitest/test_minitest_spec.rb{,.ignore}
+
 for f in test/minitest/test_*.rb
 do
 	ruby -Ilib:.:./test $f