metrics: combine time ranges for tests

Instead of getting into the weeds about how granular our messages are,
we are just making sure all the time frames of interest are tested

spec/support/metric_helper.rb

@@ -31,15 +31,29 @@ def queue_timings(items = MiqQueue.where(:method_name => %w[perf_capture_hourly
           messages[interval_name] ||= {}
           (messages[interval_name][obj] ||= []) << q.args
         end
-        messages["historical"]&.transform_values!(&:sort!)
+        messages["historical"]&.transform_values! { |v| combine_consecutive(v) }
 
         messages
       end
 
+      def combine_consecutive(array)
+        x = array.sort!.shift
+        array.each_with_object([]) do |i, ac|
+          if i.first == x.last
+            x[1] = i.last
+          else
+            ac << x
+            x = i
+          end
+        end << x
+      end
+
       # sorry, stole from the code - not really testing
       def arg_day_range(start_time, end_time, threshold = 1.day)
-        (start_time.utc..end_time.utc).step_value(threshold).each_cons(2).collect do |s_time, e_time|
-          [s_time, e_time]
+        combine_consecutive(
+          (start_time.utc..end_time.utc).step_value(threshold).each_cons(2).collect do |s_time, e_time|
+            [s_time, e_time]
+          end
         end
       end