Write task to migrate budget admins and valuators

If we didn't run this task, investments for existing budgets wouldn't
show their administrator/valuators as an option when we're editing them,
leading to data loss.

spec/lib/tasks/migrations_spec.rb

@@ -1,22 +1,68 @@
 require "rails_helper"
 
 describe "Migration tasks" do
-  let(:run_rake_task) do
-    Rake::Task["migrations:valuation_taggings"].reenable
-    Rake.application.invoke_task("migrations:valuation_taggings")
+  describe "valuation_taggins" do
+    let(:run_rake_task) do
+      Rake::Task["migrations:valuation_taggings"].reenable
+      Rake.application.invoke_task("migrations:valuation_taggings")
+    end
+
+    it "updates taggings" do
+      valuation_tagging = create(:tagging, context: "valuation")
+      another_valuation_tagging = create(:tagging, context: "valuation")
+      valuation_tags_tagging = create(:tagging, context: "valuation_tags")
+      tags_tagging = create(:tagging)
+
+      run_rake_task
+
+      expect(valuation_tagging.reload.context).to eq "valuation_tags"
+      expect(another_valuation_tagging.reload.context).to eq "valuation_tags"
+      expect(valuation_tags_tagging.reload.context).to eq "valuation_tags"
+      expect(tags_tagging.reload.context).to eq "tags"
+    end
   end
 
-  it "updates taggings" do
-    valuation_tagging = create(:tagging, context: "valuation")
-    another_valuation_tagging = create(:tagging, context: "valuation")
-    valuation_tags_tagging = create(:tagging, context: "valuation_tags")
-    tags_tagging = create(:tagging)
+  describe "budget_admins_and_valuators" do
+    let(:run_rake_task) do
+      Rake::Task["migrations:budget_admins_and_valuators"].reenable
+      Rake.application.invoke_task("migrations:budget_admins_and_valuators")
+    end
 
-    run_rake_task
+    let(:old_budget) { create(:budget) }
+    let(:current_budget) { create(:budget) }
 
-    expect(valuation_tagging.reload.context).to eq "valuation_tags"
-    expect(another_valuation_tagging.reload.context).to eq "valuation_tags"
-    expect(valuation_tags_tagging.reload.context).to eq "valuation_tags"
-    expect(tags_tagging.reload.context).to eq "tags"
+    it "assigns administrators from existing investments" do
+      harold = create(:administrator)
+      john = create(:administrator)
+      root = create(:administrator)
+
+      create(:budget_investment, budget: old_budget, administrator: john)
+      create(:budget_investment, budget: old_budget, administrator: harold)
+      create(:budget_investment, budget: old_budget, administrator: nil)
+
+      create(:budget_investment, budget: current_budget, administrator: root)
+
+      run_rake_task
+
+      expect(old_budget.administrators).to match_array [john, harold]
+      expect(current_budget.administrators).to match_array [root]
+    end
+
+    it "assigns valuators from existing investments" do
+      tyrion = create(:valuator)
+      cersei = create(:valuator)
+      jaime = create(:valuator)
+
+      create(:budget_investment, budget: old_budget, valuators: [cersei])
+      create(:budget_investment, budget: old_budget, valuators: [jaime, cersei])
+      create(:budget_investment, budget: old_budget, valuators: [])
+
+      create(:budget_investment, budget: current_budget, valuators: [tyrion, jaime])
+
+      run_rake_task
+
+      expect(old_budget.valuators).to match_array [cersei, jaime]
+      expect(current_budget.valuators).to match_array [tyrion, jaime]
+    end
   end
 end