Fix tests not running in Release

Author: ivanz

appveyor.yml

@@ -1,7 +1,7 @@
 environment:
-  nuget_version: '0.11.0-rc1'
+  nuget_version: '0.11.0-rc2'
   nuget_prerelease: true
-  assembly_version: '0.9.0.0'
+  assembly_version: '0.11.0.0'
 
 deploy:
   - provider: GitHub

build.ps1

@@ -57,7 +57,7 @@ Write-Host "Running tests..."
 
 [bool] $testsFailed = $false
 $tests | ForEach {
-    Invoke-Expression "dotnet test $($_.FullName)"
+    Invoke-Expression "dotnet test $($_.FullName) -c ${Configuration}"
 
     if (!$testsFailed) {
         $testsFailed = $LASTEXITCODE -and $LASTEXITCODE -ne 0