Make PrometheusTextFormat return proper output terminated with '\n'

app/services/metrics_service.rb

@@ -18,7 +18,7 @@ class MetricsService
   end
 
   def metrics_text
-    "#{health_metrics_text}\n#{prometheus_metrics_text}"
+    "#{health_metrics_text}#{prometheus_metrics_text}"
   end
 
   private

lib/gitlab/health_checks/prometheus_text_format.rb

@@ -2,7 +2,7 @@ module Gitlab
   module HealthChecks
     class PrometheusTextFormat
       def marshal(metrics)
-        metrics_with_type_declarations(metrics).join("\n")
+        "#{metrics_with_type_declarations(metrics).join("\n")}\n"
       end
 
       private

spec/db/production/settings.rb

-require 'spec_helper'
-
-describe 'seed production settings', lib: true do
-  include StubENV
-
-  context 'GITLAB_SHARED_RUNNERS_REGISTRATION_TOKEN is set in the environment' do
-    before do
-      stub_env('GITLAB_SHARED_RUNNERS_REGISTRATION_TOKEN', '013456789')
-    end
-
-    it 'writes the token to the database' do
-      load(File.join(__dir__, '../../../db/fixtures/production/010_settings.rb'))
-      expect(ApplicationSetting.current.runners_registration_token).to eq('013456789')
-    end
-  end
-end

spec/lib/gitlab/health_checks/prometheus_text_format_spec.rb

@@ -16,7 +16,7 @@ describe Gitlab::HealthChecks::PrometheusTextFormat do
         metric2 2
       EXPECTED
 
-      expect(subject.marshal(sample_metrics)).to eq(expected.chomp)
+      expect(subject.marshal(sample_metrics)).to eq(expected)
     end
 
     context 'metrics where name repeats' do
@@ -34,7 +34,7 @@ describe Gitlab::HealthChecks::PrometheusTextFormat do
           # TYPE metric2 gauge
           metric2 3
         EXPECTED
-        expect(subject.marshal(sample_metrics)).to eq(expected.chomp)
+        expect(subject.marshal(sample_metrics)).to eq(expected)
       end
     end
   end