Handle blank lines in Yaml.Text()

- see aaubry#886
- transform blank lines to `string.Empty`
- remove all trailing whitespace from lines
  - if trailing whitespace is significant in a future test, YAML files can be added
- `throw new ArgumentException(...)` if a line is insufficiently indented
  - should be easier to fix test than with previous `ArgumentOutOfRangeException` for this case
- add tests

YamlDotNet.Test/Serialization/SerializationTests.cs

@@ -252,7 +252,7 @@ public void DeserializeWithGapsBetweenKeys()
         {
             var yamlReader = new StringReader(@"Text: >
   Some Text.
-  
+
 Value: foo");
             var result = Deserializer.Deserialize(yamlReader);
 
@@ -1233,24 +1233,24 @@ public void ExampleFromSpecificationIsHandledCorrectly()
                   - &LEFT { x: 0, y: 2 }
                   - &BIG { r: 10 }
                   - &SMALL { r: 1 }
-                
+
                 # All the following maps are equal:
                 results:
                   - # Explicit keys
                     x: 1
                     y: 2
                     r: 10
                     label: center/big
-                  
+
                   - # Merge one map
                     << : *CENTER
                     r: 10
                     label: center/big
-                  
+
                   - # Merge multiple maps
                     << : [ *CENTER, *BIG ]
                     label: center/big
-                  
+
                   - # Override
                     << : [ *BIG, *LEFT, *SMALL ]
                     x: 1
@@ -2168,29 +2168,29 @@ public void ShouldIndentSequences()
         [Fact]
         public void ExampleFromSpecificationIsHandledCorrectlyWithLateDefine()
         {
-            var parser = new MergingParser(Yaml.ParserForText(@"               
+            var parser = new MergingParser(Yaml.ParserForText(@"
                 # All the following maps are equal:
                 results:
                   - # Explicit keys
                     x: 1
                     y: 2
                     r: 10
                     label: center/big
-                  
+
                   - # Merge one map
                     << : *CENTER
                     r: 10
                     label: center/big
-                  
+
                   - # Merge multiple maps
                     << : [ *CENTER, *BIG ]
                     label: center/big
-                  
+
                   - # Override
                     << : [ *BIG, *LEFT, *SMALL ]
                     x: 1
                     label: center/big
-                
+
                 obj:
                   - &CENTER { x: 1, y: 2 }
                   - &LEFT { x: 0, y: 2 }

YamlDotNet.Test/Yaml.cs

@@ -90,11 +90,11 @@ public static string Text(string yamlText)
         {
             var lines = yamlText
                 .Split('\n')
-                .Select(l => l.TrimEnd('\r', '\n'))
-                .SkipWhile(l => l.Trim(' ', '\t').Length == 0)
+                .Select(l => l.TrimEnd())
+                .SkipWhile(l => l.Length == 0)
                 .ToList();
 
-            while (lines.Count > 0 && lines[lines.Count - 1].Trim(' ', '\t').Length == 0)
+            while (lines.Count > 0 && lines[lines.Count - 1].Length == 0)
             {
                 lines.RemoveAt(lines.Count - 1);
             }
@@ -107,8 +107,15 @@ public static string Text(string yamlText)
                     throw new ArgumentException("Invalid indentation");
                 }
 
+                var indentation = indent.Groups[1].Length;
                 lines = lines
-                    .Select(l => l.Substring(indent.Groups[1].Length))
+                    .Select((l, num) => l.Length == 0 ?
+                        // Blank lines don't need to be indented.
+                        string.Empty :
+                        l.TakeWhile(c => c == ' ' || c == '\t').Count() < indentation ?
+                            // However, other lines must be indented at least as much as the first line.
+                            throw new ArgumentException($"Incorrectly indented line '{l}', #{num}.", nameof(yamlText)) :
+                            l.Substring(indentation))
                     .ToList();
             }
 

YamlDotNet.Test/YamlTests.cs

@@ -0,0 +1,116 @@
+// This file is part of YamlDotNet - A .NET library for YAML.
+// Copyright (c) Antoine Aubry and contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+// of the Software, and to permit persons to whom the Software is furnished to do
+// so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+using System;
+using FluentAssertions;
+using Xunit;
+
+namespace YamlDotNet.Test
+{
+    public class YamlTests
+    {
+        private const string SingleLine = "object:";
+        private const string LeadingBlankLines = @"
+
+
+object:";
+        private const string LeadingBlankLinesWithWhitespace = @"    
+    
+    
+object:";
+        private const string TrailingBlankLines = @"object:
+
+
+";
+        private const string TrailingBlankLinesWithWhitespace = @"object:
+    
+    
+";
+
+        private const string Lines = @"this:
+that:
+theOtherThing:";
+        private const string IndentedLines = @"    this:
+    that:
+    theOtherThing:";
+
+        private const string NestedLines = @"Map1:
+    Map2:
+        - entry 1
+        - entry 2
+        - entry 3";
+        private const string IndentedNestedLines = @"    Map1:
+        Map2:
+            - entry 1
+            - entry 2
+            - entry 3";
+
+        private const string SomeBlankLines = @"this:
+
+that:
+
+
+theOtherThing:";
+        private const string SomeBlankLinesWithWhitespace = @"this:
+    
+that:
+    
+    
+theOtherThing:";
+
+        [Theory]
+        [InlineData(SingleLine, SingleLine)]
+        [InlineData(LeadingBlankLines, SingleLine)]
+        [InlineData(LeadingBlankLinesWithWhitespace, SingleLine)]
+        [InlineData(TrailingBlankLines, SingleLine)]
+        [InlineData(TrailingBlankLinesWithWhitespace, SingleLine)]
+        [InlineData(Lines, Lines)]
+        [InlineData(IndentedLines, Lines)]
+        [InlineData(NestedLines, NestedLines)]
+        [InlineData(IndentedNestedLines, NestedLines)]
+        [InlineData(SomeBlankLines, SomeBlankLines)]
+        [InlineData(SomeBlankLinesWithWhitespace, SomeBlankLines)]
+        public void TextProducesExpectedOutput(string text, string expectedText)
+        {
+            expectedText = expectedText.NormalizeNewLines();
+            var result = Yaml.Text(text);
+
+            result.NormalizeNewLines().Should().Be(expectedText);
+        }
+
+        [Fact]
+        public void TextThrowsArgumentOutOfRangeExceptionForInsuffientIndentation()
+        {
+            const string BadlyIndentedLines = @"    this:
+  that:
+    theOtherThing:";
+            var expectedMessage =
+#if NETFRAMEWORK
+                "Incorrectly indented line '  that:', #1." + Environment.NewLine + "Parameter name: yamlText";
+#else
+                "Incorrectly indented line '  that:', #1. (Parameter 'yamlText')";
+#endif
+            Action act = () => Yaml.Text(BadlyIndentedLines);
+
+            act.ShouldThrowExactly<ArgumentException>().WithMessage(expectedMessage);
+        }
+    }
+}