diff --git a/lib/reline.rb b/lib/reline.rb
index f5c0f5ef69..58a03f882c 100644
--- a/lib/reline.rb
+++ b/lib/reline.rb
@@ -348,6 +348,7 @@ def readline(prompt = '', add_hist = false)
   def_single_delegators :core, :vi_editing_mode, :emacs_editing_mode
   def_single_delegators :core, :readline
   def_instance_delegators self, :readline
+  private :readline
 
 
   #--------------------------------------------------------
@@ -375,6 +376,7 @@ def self.insert_text(*args, &block)
 
   def_single_delegators :core, :readmultiline
   def_instance_delegators self, :readmultiline
+  private :readmultiline
 
   def self.core
     @core ||= Core.new { |core|
diff --git a/test/reline/test_reline.rb b/test/reline/test_reline.rb
index e5c7f525bf..d6c7bd0375 100644
--- a/test/reline/test_reline.rb
+++ b/test/reline/test_reline.rb
@@ -217,11 +217,15 @@ def test_editing_mode
   end
 
   def test_readmultiline
-    # TODO
+    # readmultiline is module function
+    assert_equal(true, Reline.methods.include?(:readmultiline))
+    assert_equal(true, Reline.private_instance_methods.include?(:readmultiline))
   end
 
   def test_readline
-    # TODO
+    # readline is module function
+    assert_equal(true, Reline.methods.include?(:readline))
+    assert_equal(true, Reline.private_instance_methods.include?(:readline))
   end
 
   def test_inner_readline