Go to investments list from a single heading group

There's no real point in linking to a page offering users to choose a
heading when there's only one heading to choose.

So we're linking to the investments index instead.

app/components/budgets/ballot/ballot_component.html.erb

@@ -23,8 +23,7 @@
           <h3>
             <%= group.name %> - <%= heading.name %>
           </h3>
-          <%= link_to sanitize(ballot.amount_available_info(heading)),
-                      budget_group_path(budget, group) %>
+          <%= link_to sanitize(ballot.amount_available_info(heading)), group_path(group) %>
         </div>
         <% if ballot.has_lines_in_group?(group) %>
           <h4 class="amount-spent text-right">
@@ -52,7 +51,7 @@
           <h3>
             <%= group.name %>
           </h3>
-          <%= link_to t("budgets.ballots.show.no_balloted_group_yet"), budget_group_path(budget, group) %>
+          <%= link_to t("budgets.ballots.show.no_balloted_group_yet"), group_path(group) %>
         </div>
       </div>
     </div>

app/components/budgets/ballot/ballot_component.rb

@@ -18,4 +18,12 @@ class Budgets::Ballot::BallotComponent < ApplicationComponent
     def no_balloted_groups
       budget.groups.sort_by_name - ballot.groups
     end
+
+    def group_path(group)
+      if group.multiple_headings?
+        budget_group_path(budget, group)
+      else
+        budget_investments_path(budget, heading_id: group.headings.first)
+      end
+    end
 end

spec/components/budgets/ballot/ballot_component_spec.rb

@@ -6,14 +6,48 @@ describe Budgets::Ballot::BallotComponent do
 
   describe "link to group" do
     let(:budget) { create(:budget, :balloting) }
+    let(:group) { create(:budget_group, budget: budget) }
     let(:ballot) { create(:budget_ballot, user: create(:user), budget: budget) }
 
-    it "displays links to vote on groups with no investments voted yet" do
-      group = create(:budget_group, budget: budget)
+    context "group with a single heading" do
+      let!(:heading) { create(:budget_heading, group: group, price: 1000) }
 
-      render_inline Budgets::Ballot::BallotComponent.new(ballot)
+      it "displays a link to vote investments when there aren't any investments in the ballot" do
+        render_inline Budgets::Ballot::BallotComponent.new(ballot)
 
-      expect(page).to have_link "You have not voted on this group yet, go vote!", href: budget_group_path(budget, group)
+        expect(page).to have_link "You have not voted on this group yet, go vote!",
+                                  href: budget_investments_path(budget, heading_id: heading.id)
+      end
+
+      it "displays a link to continue voting when there are investments in the ballot" do
+        ballot.investments << create(:budget_investment, :selected, heading: heading, price: 200)
+
+        render_inline Budgets::Ballot::BallotComponent.new(ballot)
+
+        expect(page).to have_link "Still available to you €800",
+                                  href: budget_investments_path(budget, heading_id: heading.id)
+      end
+    end
+
+    context "group with multiple headings" do
+      let!(:heading) { create(:budget_heading, group: group, price: 1000) }
+      before { create(:budget_heading, group: group) }
+
+      it "displays a link to vote on a heading when there aren't any investments in the ballot" do
+        render_inline Budgets::Ballot::BallotComponent.new(ballot)
+
+        expect(page).to have_link "You have not voted on this group yet, go vote!",
+                                  href: budget_group_path(budget, group)
+      end
+
+      it "displays a link to change the heading when there are invesments in the ballot" do
+        ballot.investments << create(:budget_investment, :selected, heading: heading, price: 200)
+
+        render_inline Budgets::Ballot::BallotComponent.new(ballot)
+
+        expect(page).to have_link "Still available to you €800",
+                                  href: budget_group_path(budget, group)
+      end
     end
   end
 end