diff --git a/tests/runtests.ps1 b/tests/runtests.ps1
index b3f351e..e402540 100644
--- a/tests/runtests.ps1
+++ b/tests/runtests.ps1
@@ -16,7 +16,7 @@ if ($lastexitcode -ne 0) {
 }
 
 echo "checking for critical files..."
-$s=(docker run --rm -i tier/shibbidp_novm_windows powershell Get-Childitem c:/opt/shibboleth-idp/credentials/ -Name).Count
+$s=(docker run --rm -i $fullimagename powershell Get-Childitem c:/opt/shibboleth-idp/credentials/ -Name).Count
 if ( $s -gt 6 ) { $lastexitcode="0" } else { $lastexitcode="1"; echo "credentials folder missing files..."; exit 1 }