Temp folder location on Linux

Author: nblumhardt

test/Serilog.Sinks.File.Tests/Serilog.Sinks.File.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net452;netcoreapp2.0</TargetFrameworks>
+    <TargetFrameworks>net452;netcoreapp1.0;netcoreapp2.0</TargetFrameworks>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <AssemblyName>Serilog.Sinks.File.Tests</AssemblyName>
     <AssemblyOriginatorKeyFile>../../assets/Serilog.snk</AssemblyOriginatorKeyFile>

test/Serilog.Sinks.File.Tests/Support/TempFolder.cs

@@ -14,7 +14,7 @@ class TempFolder : IDisposable
         public TempFolder(string name)
         {
             _tempFolder = System.IO.Path.Combine(
-                Environment.GetEnvironmentVariable("TMP"),
+                Environment.GetEnvironmentVariable("TMP") ?? Environment.GetEnvironmentVariable("TMPDIR") ?? "/tmp",
                 "Serilog.Sinks.File.Tests",
                 Session.ToString("n"),
                 name);