Fix block chomping and add more tests

When no [chomping indicator][1] is specified for a folded or literal
block, then YAML parser should preserve the final line break (i.e. the
string should end with \n). This implies that when dumping a string
*without* the trailing newline to YAML, we should specify the stripping
indicator (-).

[1]: http://yaml.org/spec/1.2/2009-07-21/spec.html#id2593651

2 files changed, 30 insertions, 9 deletions

diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index ba1ac13..f6427ce 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -319,7 +319,6 @@ module Psych
           quote = false
         elsif @line_width && o.length > @line_width
           style = Nodes::Scalar::FOLDED
-          o += "\n" unless o =~ /\n\Z/  # to avoid non-default chomping indicator
         elsif o =~ /^[^[:word:]][^"]*$/
           style = Nodes::Scalar::DOUBLE_QUOTED
         elsif not String === @ss.tokenize(o)
diff --git a/test/psych/test_string.rb b/test/psych/test_string.rb
index 3188b5c..df8fb98 100644
--- a/test/psych/test_string.rb
+++ b/test/psych/test_string.rb
@@ -30,32 +30,54 @@ module Psych
     end
 
     def test_doublequotes_when_there_is_a_single
-      yaml = Psych.dump "@123'abc"
-      assert_match(/---\s*"/, yaml)
+      str = "@123'abc"
+      yaml = Psych.dump str
+      assert_match /---\s*"/, yaml
+      assert_equal str, Psych.load(yaml)
     end
 
-    def test_plain_when_shorten_than_line_width
+    def test_plain_when_shorten_than_line_width_and_no_final_line_break
       str = "Lorem ipsum"
       yaml = Psych.dump str, line_width: 12
       assert_match /---\s*[^>|]+\n/, yaml
+      assert_equal str, Psych.load(yaml)
     end
 
-    def test_folded_when_longer_than_line_width_and_no_newlines
-      str = "Lorem ipsum dolor sit amet, consectetur"
+    def test_plain_when_shorten_than_line_width_and_with_final_line_break
+      str = "Lorem ipsum\n"
       yaml = Psych.dump str, line_width: 12
-      assert_match /---\s*>\n(.*\n){3}\Z/, yaml
+      assert_match /---\s*[^>|]+\n/, yaml
+      assert_equal str, Psych.load(yaml)
     end
 
-    def test_folded_when_longer_than_line_width_and_trailing_newline
+    def test_folded_when_longer_than_line_width_and_with_final_line_break
       str = "Lorem ipsum dolor sit\n"
       yaml = Psych.dump str, line_width: 12
       assert_match /---\s*>\n(.*\n){2}\Z/, yaml
+      assert_equal str, Psych.load(yaml)
     end
 
-    def test_literal_when_inner_newline
+    # http://yaml.org/spec/1.2/2009-07-21/spec.html#id2593651
+    def test_folded_strip_when_longer_than_line_width_and_no_newlines
+      str = "Lorem ipsum dolor sit amet, consectetur"
+      yaml = Psych.dump str, line_width: 12
+      assert_match /---\s*>-\n(.*\n){3}\Z/, yaml
+      assert_equal str, Psych.load(yaml)
+    end
+
+    def test_literal_when_inner_and_final_line_break
       str = "Lorem ipsum\ndolor\n"
       yaml = Psych.dump str, line_width: 12
       assert_match /---\s*|\n(.*\n){2}\Z/, yaml
+      assert_equal str, Psych.load(yaml)
+    end
+
+    # http://yaml.org/spec/1.2/2009-07-21/spec.html#id2593651
+    def test_literal_strip_when_inner_line_break_and_no_final_line_break
+      str = "Lorem ipsum\ndolor"
+      yaml = Psych.dump str, line_width: 12
+      assert_match /---\s*|-\n(.*\n){2}\Z/, yaml
+      assert_equal str, Psych.load(yaml)
     end
 
     def test_cycle_x