Add preliminary Win/Nix switch

Author: ilkerde

TestingHelpers/CrossPlatformExtensions.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace System.IO.Abstractions.TestingHelpers
+{
+    public static class XFS
+    {
+        public static string ForWin(string path)
+        {
+            return path;
+        }
+
+        public static string ForUnix(this string path, string unixPath)
+        {
+            int p = (int) Environment.OSVersion.Platform;
+            bool isUnix = (p == 4) || (p == 6) || (p == 128);
+
+            return isUnix ? unixPath : path;
+        }
+    }
+}

TestingHelpers/TestingHelpers.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProductVersion>9.0.30729</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{251BD5E5-8133-47A4-AB19-17CF0F43D6AE}</ProjectGuid>
     <OutputType>Library</OutputType>
     <AppDesignerFolder>Properties</AppDesignerFolder>
@@ -43,7 +41,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
-    <SignAssembly>false</SignAssembly>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
     <DebugType>pdbonly</DebugType>
@@ -79,6 +76,7 @@
     <Compile Include="MockPath.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="StringExtensions.cs" />
+    <Compile Include="CrossPlatformExtensions.cs" />
   </ItemGroup>
   <ItemGroup>
     <BootstrapperPackage Include="Microsoft.Net.Client.3.5">