diff --git a/spec/defines/manage_dropin_spec.rb b/spec/defines/manage_dropin_spec.rb
index aa0f9985..d80c12f6 100644
--- a/spec/defines/manage_dropin_spec.rb
+++ b/spec/defines/manage_dropin_spec.rb
@@ -17,6 +17,9 @@
             }
           end
 
+          it { is_expected.to compile.with_all_deps }
+          it { is_expected.to contain_systemd__dropin_file('foobar.conf').with_content(%r{^# Deployed with puppet$}) }
+
           context 'setting some parameters simply' do
             let(:params) do
               super().merge(
diff --git a/templates/unit_file.epp b/templates/unit_file.epp
index 6495aa49..29e698ce 100644
--- a/templates/unit_file.epp
+++ b/templates/unit_file.epp
@@ -4,6 +4,7 @@
  Optional[Hash] $install_entry,
  Optional[Hash] $timer_entry,
 | -%>
+# Deployed with puppet
 <% if $unit_entry { -%>
 
 [Unit]