Add method to easily access a local target by code

Similar to what we do in goals and targets.

app/models/sdg/local_target.rb

@@ -17,6 +17,10 @@ class SDG::LocalTarget < ApplicationRecord
 
   belongs_to :target
 
+  def self.[](code)
+    find_by!(code: code)
+  end
+
   def <=>(any_target)
     if any_target.class == self.class
       [target, numeric_subcode] <=> [any_target.target, any_target.numeric_subcode]

spec/models/sdg/local_target_spec.rb

@@ -82,4 +82,16 @@ describe SDG::LocalTarget do
       expect(local_target).to be < greater_target
     end
   end
+
+  describe ".[]" do
+    it "finds existing local targets by code" do
+      create(:sdg_local_target, code: "1.1.1")
+
+      expect(SDG::LocalTarget["1.1.1"].code).to eq "1.1.1"
+    end
+
+    it "raises an exception for non-existing codes" do
+      expect { SDG::LocalTarget["1.1.99"] }.to raise_exception ActiveRecord::RecordNotFound
+    end
+  end
 end

spec/system/sdg_management/relations_spec.rb

@@ -168,11 +168,10 @@ describe "SDG Relations", :js do
       end
 
       scenario "local target filter" do
-        schools = create(:sdg_local_target, code: "4.1.1")
-        teachers = create(:sdg_local_target, code: "4.1.2")
-
-        create(:debate, title: "Rebuild local schools", sdg_local_targets: [schools])
-        create(:debate, title: "Hire teachers", sdg_local_targets: [teachers])
+        create(:sdg_local_target, code: "4.1.1")
+        create(:sdg_local_target, code: "4.1.2")
+        create(:debate, title: "Rebuild local schools", sdg_local_targets: [SDG::LocalTarget["4.1.1"]])
+        create(:debate, title: "Hire teachers", sdg_local_targets: [SDG::LocalTarget["4.1.2"]])
 
         visit sdg_management_debates_path
         select "4.1.1", from: "target_code"