Hide group name only on budgets with one group

In the form of creating a new investment was hiding the name of the
group if it had only one heading, but could be confusing to users if
there are, for example, five different groups of one heading.

The solution:

- If the budget has one group and one heading, the heading selector is
  hidden.
- If the budget has one group and more than one heading, the group name
  is hidden.
- If the budget has more than one group, the group name appears
  regardless of the number of headings.

app/models/budget.rb

@@ -162,8 +162,12 @@ class Budget < ApplicationRecord
     current_phase&.balloting_or_later?
   end
 
+  def single_group?
+    groups.one?
+  end
+
   def single_heading?
-    groups.one? && headings.one?
+    single_group? && headings.one?
   end
 
   def heading_price(heading)

app/models/budget/group.rb

@@ -30,10 +30,6 @@ class Budget
       all.sort_by(&:name)
     end
 
-    def single_heading_group?
-      headings.count == 1
-    end
-
     private
 
       def generate_slug?

app/models/budget/heading.rb

@@ -48,7 +48,7 @@ class Budget
     end
 
     def name_scoped_by_group
-      group.single_heading_group? ? name : "#{group.name}: #{name}"
+      budget.single_group? ? name : "#{group.name}: #{name}"
     end
 
     def can_be_deleted?

spec/models/budget/heading_spec.rb

@@ -332,4 +332,33 @@ describe Budget::Heading do
       expect(build(:budget_heading, max_ballot_lines: 0)).not_to be_valid
     end
   end
+
+  describe "#name_scoped_by_group" do
+    it "returns heading name in budgets with a single heading" do
+      heading = create(:budget_heading, group: group, name: "One and only")
+
+      expect(heading.name_scoped_by_group).to eq "One and only"
+    end
+
+    it "returns heading name in budgets with one group and many headings" do
+      schools = create(:budget_heading, group: group, name: "Schools")
+      universities = create(:budget_heading, group: group, name: "Universities")
+
+      expect(schools.name_scoped_by_group).to eq "Schools"
+      expect(universities.name_scoped_by_group).to eq "Universities"
+    end
+
+    it "returns heading name in groups with many headings in budgets with many groups" do
+      education = create(:budget_group, budget: budget, name: "Education")
+      health = create(:budget_group, budget: budget, name: "Health")
+
+      schools = create(:budget_heading, group: education, name: "Schools")
+      universities = create(:budget_heading, group: education, name: "Universities")
+      supplies = create(:budget_heading, group: health, name: "Medical supplies")
+
+      expect(schools.name_scoped_by_group).to eq "Education: Schools"
+      expect(universities.name_scoped_by_group).to eq "Education: Universities"
+      expect(supplies.name_scoped_by_group).to eq "Health: Medical supplies"
+    end
+  end
 end

spec/system/admin/budget_investments_spec.rb

@@ -101,7 +101,7 @@ describe "Admin budget investments", :admin do
       expect(page).to have_link("Change name")
       expect(page).to have_link("Plant trees")
 
-      select "Central Park", from: "heading_id"
+      select "Parks: Central Park", from: "heading_id"
       click_button "Filter"
 
       expect(page).not_to have_link("Realocate visitors")
@@ -1040,7 +1040,7 @@ describe "Admin budget investments", :admin do
 
       fill_in "Title", with: "Potatoes"
       fill_in_ckeditor "Description", with: "Carrots"
-      select "#{budget_investment.group.name}: Barbate", from: "budget_investment[heading_id]"
+      select "Barbate", from: "budget_investment[heading_id]"
       uncheck "budget_investment_incompatible"
       check "budget_investment_selected"
 

spec/system/budgets/investments_spec.rb

@@ -570,18 +570,35 @@ describe "Budget Investments" do
       expect(page).to have_content "Build a skyscraper"
     end
 
-    scenario "Create with multiple headings" do
-      create(:budget_heading, budget: budget, name: "Medical supplies")
-      create(:budget_heading, budget: budget, name: "Even more hospitals")
+    scenario "Create with single group and multiple headings" do
+      create(:budget_heading, group: group, name: "Medical supplies")
+      create(:budget_heading, group: group, name: "Even more hospitals")
+
+      login_as(author)
+
+      visit new_budget_investment_path(budget)
+
+      expect(page).to have_select "Heading",
+        options: ["", "More hospitals", "Medical supplies", "Even more hospitals"]
+      expect(page).not_to have_content "Health"
+    end
+
+    scenario "Create with multiple groups" do
+      education = create(:budget_group, budget: budget, name: "Education")
+
+      create(:budget_heading, group: group, name: "Medical supplies")
+      create(:budget_heading, group: education, name: "Schools")
+
       login_as(author)
 
       visit new_budget_investment_path(budget)
 
       expect(page).not_to have_content("#{heading.name} (#{budget.formatted_heading_price(heading)})")
       expect(page).to have_select "Heading",
-        options: ["", "More hospitals", "Medical supplies", "Even more hospitals"]
+        options: ["", "Health: More hospitals", "Health: Medical supplies", "Education: Schools"]
+
+      select "Health: Medical supplies", from: "Heading"
 
-      select "Medical supplies", from: "Heading"
       fill_in "Title", with: "Build a skyscraper"
       fill_in_ckeditor "Description", with: "I want to live in a high tower over the clouds"
       fill_in "Location additional info", with: "City center"
@@ -755,7 +772,7 @@ describe "Budget Investments" do
 
       select_options = find("#budget_investment_heading_id").all("option").map(&:text)
       expect(select_options).to eq ["",
-                                    "Toda la ciudad",
+                                    "Toda la ciudad: Toda la ciudad",
                                     "Health: More health professionals",
                                     "Health: More hospitals"]
     end

spec/system/management/budget_investments_spec.rb

@@ -396,7 +396,7 @@ describe "Budget Investments" do
         expect(page).to have_content(low_investment.title)
       end
 
-      select "Whole city: District Nine", from: "heading_id"
+      select "District Nine", from: "heading_id"
       click_button("Search")
 
       within "#budget-investments" do