1 files changed, 12 insertions, 0 deletions
diff --git a/test/io.rb b/test/io.rb
index ee0432b14..da94360d7 100644
--- a/test/io.rb
+++ b/test/io.rb
@@ -262,6 +262,18 @@ assert('IO#_read_buf') do
   io.closed?
 end
 
+assert('IO#isatty') do
+  f1 = File.open("/dev/tty")
+  f2 = File.open($mrbtest_io_rfname)
+
+  assert_true  f1.isatty
+  assert_false f2.isatty
+
+  f1.close
+  f2.close
+  true
+end
+
 assert('IO#pos=, IO#seek') do
   fd = IO.sysopen $mrbtest_io_rfname
   io = IO.new fd