diff --git a/test/test_rfc2047.rb b/test/test_rfc2047.rb
index 09429e0..16244d2 100644
--- a/test/test_rfc2047.rb
+++ b/test/test_rfc2047.rb
@@ -23,7 +23,7 @@ def test_q_decode_utf8_ascii()
   end
 
   def test_q_decode_end_equal()
-    assert_equal("abc", MailParser::RFC2047.q_decode("abc="))
+    assert_match(/\Aabc=?\z/, MailParser::RFC2047.q_decode("abc="))
   end
 
   def test_b_decode_ascii()