diff --git a/pkgs/mruby/test/ntoa.rb b/pkgs/mruby/test/ntoa.rb
index 7ca998d..cb53e8d 100644
--- a/pkgs/mruby/test/ntoa.rb
+++ b/pkgs/mruby/test/ntoa.rb
@@ -205,8 +205,8 @@ end
 
 assert 'KernAux.utoa8' do
   test_utoa8 0, '0o0'
-  test_utoa8 01, '0o1'
-  test_utoa8 0123, '0o123'
+  test_utoa8 0o1, '0o1'
+  test_utoa8 0o123, '0o123'
   test_utoa8 2**32 - 1, "0o#{(2**32 - 1).to_s(8)}"
 
   assert_raise RangeError, 'can\'t convert negative number to uint64_t' do
@@ -216,10 +216,10 @@ end
 
 assert 'KernAux.itoa8' do
   test_itoa8 0, '0o0'
-  test_itoa8 01, '0o1'
-  test_itoa8(-01, '-0o1')
-  test_itoa8 0123, '0o123'
-  test_itoa8(-0123, '-0o123')
+  test_itoa8 0o1, '0o1'
+  test_itoa8(-0o1, '-0o1')
+  test_itoa8 0o123, '0o123'
+  test_itoa8(-0o123, '-0o123')
   test_itoa8 2**31 - 1, "0o#{(2**31 - 1).to_s(8)}"
   test_itoa8(-2**31, "-0o#{(2**31).to_s(8)}")
 end