Empty instances of MapLocation won't result in a new DB record (#2220)

spec/lib/tasks/map_location_spec.rb

@@ -0,0 +1,22 @@
+require 'rake'
+require 'rails_helper'
+Rails.application.load_tasks
+
+describe 'rake map_locations:destroy' do
+  before do
+    create(:map_location, :proposal_map_location)
+    empty_location = create(:map_location, :proposal_map_location)
+    empty_location.attributes = { longitude: nil, latitude: nil, zoom: nil }
+    empty_location.save(validate: false)
+  end
+
+  let :run_rake_task do
+    Rake.application.invoke_task('map_locations:destroy')
+  end
+
+  it 'destroys empty locations' do
+    expect(MapLocation.all.size).to eq(2)
+    run_rake_task
+    expect(MapLocation.all.size).to eq(1)
+  end
+end