Allow to run etl:rerun_main for a single date

We are often asked to do this.

lib/tasks/etl.rake

@@ -83,9 +83,10 @@ namespace :etl do
   desc "Run ETL Main process across a range of dates"
   task :rerun_main, %i[from to] => [:environment] do |_t, args|
     from = args[:from].to_date
-    to = args[:to].to_date
+    to = args[:to]&.to_date
     date_range = (from..to)
-    date_range.each do |date|
+
+    date_range.compact.each do |date|
       puts "Running Etl::Main process for #{date}"
       unless Etl::Main::MainProcessor.process(date:)
         abort("Etl::Main::MainProcessor failed")

spec/tasks/etl_spec.rb

@@ -99,19 +99,34 @@
       create :metric, edition:, date: "2018-11-02"
       create :metric, edition:, date: "2018-11-03"
       Rake::Task["etl:rerun_main"].reenable
-      Rake::Task["etl:rerun_main"].invoke("2018-10-31", "2018-11-02")
     end
 
-    it "calls Etl::Main::MainProcessor.process with each date" do
+    it "calls Etl::Main::MainProcessor.process with each date when a range is provided" do
+      Rake::Task["etl:rerun_main"].invoke("2018-10-31", "2018-11-02")
+
       [Date.new(2018, 10, 31), Date.new(2018, 11, 1), Date.new(2018, 11, 2)].each do |date|
         expect(processor).to have_received(:process).once.with(date:)
       end
     end
 
     it "runs the aggregations process for each month in the range" do
+      Rake::Task["etl:rerun_main"].invoke("2018-10-31", "2018-11-02")
+
       [Date.new(2018, 10, 31), Date.new(2018, 11, 30)].each do |date|
         expect(processor).to have_received(:process_aggregations).once.with(date:)
       end
     end
+
+    it "calls Etl::Main::MainProcessor.process for a single date" do
+      Rake::Task["etl:rerun_main"].invoke("2018-10-31")
+
+      expect(processor).to have_received(:process).once.with(Date.new(2018, 10, 31))
+    end
+
+    it "runs the aggregations process for a month" do
+      Rake::Task["etl:rerun_main"].invoke("2018-10-31")
+
+      expect(processor).to have_received(:process_aggregations).once.with(Date.new(2018, 10, 31))
+    end
   end
 end