Fix issue #418, modify version screen to print a new line at the end (#443)

* Fix issue #418, modify version screen to print a new line at the end

* Move unit test to a separate file

Author: moh-hassan

src/CommandLine/Text/HelpText.cs

@@ -392,7 +392,7 @@ public static HelpText AutoBuild<T>(ParserResult<T> parserResult, int maxDisplay
             var errors = ((NotParsed<T>)parserResult).Errors;
 
             if (errors.Any(e => e.Tag == ErrorType.VersionRequestedError))
-                return new HelpText(HeadingInfo.Default){MaximumDisplayWidth = maxDisplayWidth }.AddPreOptionsLine(Environment.NewLine);
+                return new HelpText($"{HeadingInfo.Default}{Environment.NewLine}"){MaximumDisplayWidth = maxDisplayWidth }.AddPreOptionsLine(Environment.NewLine);
 
             if (!errors.Any(e => e.Tag == ErrorType.HelpVerbRequestedError))
                 return AutoBuild(parserResult, current => DefaultParsingErrorsHandler(parserResult, current), e => e, maxDisplayWidth: maxDisplayWidth);

tests/CommandLine.Tests/Unit/Issue418Tests.cs

@@ -0,0 +1,36 @@
+using CommandLine.Text;
+using System;
+using System.IO;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using CommandLine.Tests.Fakes;
+using Xunit;
+using FluentAssertions;
+
+namespace CommandLine.Tests.Unit
+{
+	 //issue#418, --version does not print a new line at the end cause trouble in Linux
+    public class Issue418Tests
+    {	
+		
+        [Fact]
+        public void Explicit_version_request_generates_version_info_screen_with_eol()
+        {
+            // Fixture setup
+            var help = new StringWriter();
+            var sut = new Parser(config => config.HelpWriter = help);
+
+            // Exercize system
+            sut.ParseArguments<Simple_Options>(new[] { "--version" });
+            var result = help.ToString();           
+            // Verify outcome
+            var lines = result.ToNotEmptyLines();  
+            result.Length.Should().BeGreaterThan(0);			
+            result.Should().EndWith(Environment.NewLine);
+            result.ToNotEmptyLines().Length.Should().Be(1);
+           
+            // Teardown
+        }
+	}
+}

tests/CommandLine.Tests/Unit/ParserTests.cs

@@ -802,6 +802,7 @@ public void Parse_options_with_shuffled_index_values()
                     Assert.Equal("one", args.Arg1);
                     Assert.Equal("two", args.Arg2);
                 });
+
         }
 
 
@@ -823,5 +824,6 @@ public void Blank_lines_are_inserted_between_verbs()
             lines[10].Should().BeEquivalentTo("version    Display version information.");
             // Teardown
         }
+
     }
 }