Add test Reline::Unicode.test_get_mbchar_width.

Author: osyo-manga

test/reline/test_unicode.rb

@@ -0,0 +1,12 @@
+require_relative 'helper'
+require "reline/unicode"
+
+class Reline::Unicode::Test < Reline::TestCase
+  def setup
+    Reline.send(:test_mode)
+  end
+
+  def test_get_mbchar_width
+    assert_equal Reline.ambiguous_width, Reline::Unicode.get_mbchar_width('é')
+  end
+end