Refactor concept of current budget

When there was only one budget this implementation worked fine

Nowadays there can be multiple budgets, and therefore the definition of
the current_budget has changed. It is no longer a budget that has not
finished, but rather, the last budget created that is not in the
initial drafting phase.

Budgets in the drafting phase are not considered the current_budget,
but rather a budget that is still being prepared and that soon will
become the current_budget

app/models/budget.rb

@@ -31,7 +31,9 @@ class Budget < ActiveRecord::Base
   scope :reviewing_ballots, -> { where(phase: "reviewing_ballots") }
   scope :finished, -> { where(phase: "finished") }
 
-  scope :current, -> { where.not(phase: "finished") }
+  def self.current
+    where.not(phase: "drafting").last
+  end
 
   def description
     send("description_#{phase}").try(:html_safe)
@@ -93,10 +95,6 @@ class Budget < ActiveRecord::Base
     balloting_process? || finished?
   end
 
-  def current?
-    !finished?
-  end
-
   def heading_price(heading)
     heading_ids.include?(heading.id) ? heading.price : -1
   end

spec/models/budget_spec.rb

@@ -98,6 +98,31 @@ describe Budget do
     end
   end
 
+  describe "#current" do
+
+    it "returns nil if there is only one budget and it is still in drafting phase" do
+      budget = create(:budget, phase: "drafting")
+
+      expect(Budget.current).to eq(nil)
+    end
+
+    it "returns the budget if there is only one and not in drafting phase" do
+      budget = create(:budget, phase: "accepting")
+
+      expect(Budget.current).to eq(budget)
+    end
+
+    it "returns the last budget created that is not in drafting phase" do
+      old_budget      = create(:budget, phase: "finished",  created_at: 2.years.ago)
+      previous_budget = create(:budget, phase: "accepting", created_at: 1.year.ago)
+      current_budget  = create(:budget, phase: "accepting", created_at: 1.month.ago)
+      next_budget     = create(:budget, phase: "drafting",  created_at: 1.week.ago)
+
+      expect(Budget.current).to eq(current_budget)
+    end
+
+  end
+
   describe "heading_price" do
     let(:budget) { create(:budget) }
     let(:group) { create(:budget_group, budget: budget) }