diff --git a/mrbgems/mruby-compar-ext/test/compar.rb b/mrbgems/mruby-compar-ext/test/compar.rb
new file mode 100644
index 000000000..40d90f193
--- /dev/null
+++ b/mrbgems/mruby-compar-ext/test/compar.rb
@@ -0,0 +1,21 @@
+assert("Comparable#clamp") do
+  assert_equal(12, 12.clamp(0, 100))
+  assert_equal(100, 532.clamp(0, 100))
+  assert_equal(0, -3.123.clamp(0, 100))
+  assert_equal('d', 'd'.clamp('a', 'f'))
+  assert_equal('f', 'z'.clamp('a', 'f'))
+
+  assert_equal(12, 12.clamp(0..100))
+  assert_equal(100, 523.clamp(0..100))
+  assert_equal(0, -3.123.clamp(0..100))
+
+  assert_equal('d', 'd'.clamp('a'..'f'))
+  assert_equal('f', 'z'.clamp('a'..'f'))
+
+  assert_equal(0, -20.clamp(0..))
+  assert_equal(100, 523.clamp(..100))
+
+  assert_raise(ArgumentError) {
+    100.clamp(0...100)
+  }
+end