round trip empty strings

2 files changed, 3 insertions, 5 deletions

diff --git a/lib/psych/visitors/yast_builder.rb b/lib/psych/visitors/yast_builder.rb
index 90dc8d0..52eae59 100644
--- a/lib/psych/visitors/yast_builder.rb
+++ b/lib/psych/visitors/yast_builder.rb
@@ -21,7 +21,7 @@ module Psych
       end
 
       def visit_String o
-        quote = !!(o =~ /^(null|~)$/i)
+        quote = !!(o =~ /^(null|~)$/i or o.empty?)
 
         scalar = Nodes::Scalar.new(o, nil, nil, !quote, quote)
         @stack.last.children << scalar
diff --git a/test/visitors/test_yast_builder.rb b/test/visitors/test_yast_builder.rb
index 67d54be..bcf0cd2 100644
--- a/test/visitors/test_yast_builder.rb
+++ b/test/visitors/test_yast_builder.rb
@@ -9,10 +9,8 @@ module Psych
       end
 
       def test_scalar
-        @v.accept 'foo'
-
-        assert_equal 'foo', Psych.load(@v.tree.to_yaml)
-        assert_equal 'foo', Psych.load('foo'.to_yaml)
+        assert_round_trip 'foo'
+        assert_round_trip ''
       end
 
       def test_binary