diff --git a/appveyor.yml b/appveyor.yml
index 16d9a67..469c8b6 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -9,6 +9,8 @@
     - gh-pages
 # Build worker image (VM template)
 image: Visual Studio 2015
+environment:
+  AppVeyor: APPVEYOR
 
 # enable patching of AssemblyInfo.* files
 assembly_info:
@@ -17,7 +19,7 @@
   assembly_version: "{version}"
   assembly_file_version: "{version}"
   assembly_informational_version: "{version}"
-  
+
 #---------------------------------#
 #       build configuration       #
 #---------------------------------#
@@ -29,10 +31,10 @@
   parallel: true                                            # enable MSBuild parallel builds
   project: ClosedXML.sln       # path to Visual Studio solution or project
   verbosity: minimal
- 
+
 configuration : Release
 
 #Restore
 before_build:
   - nuget restore
-  
+