diff --git a/Nuclex.Windows.Forms.csproj b/Nuclex.Windows.Forms.csproj
index cc9db0a..9924562 100644
--- a/Nuclex.Windows.Forms.csproj
+++ b/Nuclex.Windows.Forms.csproj
@@ -19,7 +19,7 @@
     <DebugType>full</DebugType>
     <Optimize>false</Optimize>
     <OutputPath>bin\x86\Debug</OutputPath>
-    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <DefineConstants>TRACE;DEBUG;UNITTEST</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>
@@ -31,7 +31,7 @@
     <DebugType>pdbonly</DebugType>
     <Optimize>true</Optimize>
     <OutputPath>bin\x86\Release</OutputPath>
-    <DefineConstants>TRACE</DefineConstants>
+    <DefineConstants>TRACE;UNITTEST</DefineConstants>
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
     <NoStdLib>true</NoStdLib>