Add test for #70

Author: Per Gårdebrink

tests/CommandLine.Tests/Fakes/Mutable_Without_Empty_Constructor.cs

@@ -0,0 +1,19 @@
+// Copyright 2005-2015 Giacomo Stelluti Scala & Contributors. All rights reserved. See License.md in the project root for license information.
+
+namespace CommandLine.Tests.Fakes 
+{
+    class Mutable_Without_Empty_Constructor 
+    {
+        [Option("amend", HelpText = "Used to amend the tip of the current branch.")]
+        public bool Amend { get; set; }
+
+        private Mutable_Without_Empty_Constructor() 
+        {
+        }
+
+        public static Mutable_Without_Empty_Constructor Create() 
+        {
+            return new Mutable_Without_Empty_Constructor();
+        }
+    }
+}

tests/CommandLine.Tests/Unit/Issue70Tests.cs

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+using System.Linq;
+using CommandLine.Tests.Fakes;
+using CommandLine.Text;
+using FluentAssertions;
+using Xunit;
+using Xunit.Abstractions;
+
+//Issue #70
+//When the factory overload is used for ParseArguments, there should be no constraint not having an empty constructor.
+
+namespace CommandLine.Tests.Unit
+{
+    public class Issue70Tests
+    {
+        [Fact]
+        public void Create_instance_with_factory_method_should_not_fail()
+        {
+            bool actual = false;
+
+            var arguments = new[] { "--amend" };
+            var result = Parser.Default.ParseArguments(() => Mutable_Without_Empty_Constructor.Create(), arguments);
+            result.WithParsed(options => {
+                actual = options.Amend;
+            });
+
+            actual.Should().BeTrue();
+        }
+    }
+}