link Log4NetAssert into the test project #314

Tests had no access to IsFatal or the EnsureNotNull family and hand-rolled the
checks instead. Linking it needs NotNullAttribute and ValidatedNotNullAttribute
too, or the compiler reports CS0122.

Author: FreeAndNil

src/log4net.Tests/log4net.Tests.csproj

@@ -22,6 +22,9 @@
     <Compile Include="..\log4net\Util\CallerAssembly.cs" Link="Util\CallerAssembly.cs" />
     <Compile Include="..\log4net\Diagnostics\CodeAnalysis\CallerArgumentExpressionAttribute.cs" Link="Diagnostics\CodeAnalysis\CallerArgumentExpressionAttribute.cs" />
     <Compile Include="..\log4net\Diagnostics\CodeAnalysis\IsExternalInit.cs" Link="Diagnostics\CodeAnalysis\IsExternalInit.cs" />
+    <Compile Include="..\log4net\Diagnostics\CodeAnalysis\NotNullAttribute.cs" Link="Diagnostics\CodeAnalysis\NotNullAttribute.cs" />
+    <Compile Include="..\log4net\Diagnostics\CodeAnalysis\ValidatedNotNullAttribute.cs" Link="Diagnostics\CodeAnalysis\ValidatedNotNullAttribute.cs" />
+    <Compile Include="..\log4net\Util\Log4NetAssert.cs" Link="Util\Log4NetAssert.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\log4net\log4net.csproj" />