fixup! Add :most_recent aggregation to DirectFileStore

Author: Daniel Magliola

spec/prometheus/client/data_stores/direct_file_store_spec.rb

@@ -14,7 +14,7 @@
 
   it_behaves_like Prometheus::Client::DataStores
 
-  it "only accepts valid :aggregation as Metric Settings" do
+  it "only accepts valid :aggregation values as Metric Settings" do
     expect do
       subject.for_metric(:metric_name,
                          metric_type: :counter,
@@ -26,14 +26,18 @@
                          metric_type: :counter,
                          metric_settings: { aggregation: :invalid })
     end.to raise_error(Prometheus::Client::DataStores::DirectFileStore::InvalidStoreSettingsError)
+  end
 
+  it "only accepts valid keys as Metric Settings" do
+    # the only valid key at the moment is :aggregation
     expect do
       subject.for_metric(:metric_name,
                          metric_type: :counter,
                          metric_settings: { some_setting: true })
     end.to raise_error(Prometheus::Client::DataStores::DirectFileStore::InvalidStoreSettingsError)
+  end
 
-    # :most_recent aggregation can only be used for gauges
+  it "only accepts :most_recent aggregation for gauges" do
     expect do
       subject.for_metric(:metric_name,
                          metric_type: :gauge,