Add import task for la links

app/services/imports/local_authority_links_service.rb

@@ -0,0 +1,22 @@
+require "csv"
+
+module Imports
+  class LocalAuthorityLinksService
+    attr_reader :path, :count
+
+    def initialize(path:)
+      @path = path
+      @count = 0
+    end
+
+    def call
+      CSV.foreach(path, headers: true) do |row|
+        LocalAuthorityLink.upsert(
+          { local_authority_id: LocalAuthority.find_by(code: row["local_authority_code"]).id,
+            linked_local_authority_id: LocalAuthority.find_by(code: row["linked_local_authority_code"]).id },
+        )
+        @count += 1
+      end
+    end
+  end
+end

config/local_authorities_data/local_authority_links_2023.csv

@@ -0,0 +1,35 @@
+local_authority_code,linked_local_authority_code
+E06000063,E07000027
+E06000063,E07000030
+E06000063,E07000031
+E07000027,E06000063
+E07000030,E06000063
+E07000031,E06000063
+E06000064,E07000026
+E06000064,E07000028
+E06000064,E07000029
+E07000026,E06000064
+E07000028,E06000064
+E07000029,E06000064
+E06000065,E07000163
+E06000065,E07000164
+E06000065,E07000165
+E06000065,E07000166
+E06000065,E07000167
+E06000065,E07000168
+E06000065,E07000169
+E07000163,E06000065
+E07000164,E06000065
+E07000165,E06000065
+E07000166,E06000065
+E07000167,E06000065
+E07000168,E06000065
+E07000169,E06000065
+E06000066,E07000187
+E06000066,E07000188
+E06000066,E07000246
+E06000066,E07000189
+E07000187,E06000066
+E07000188,E06000066
+E07000246,E06000066
+E07000189,E06000066

lib/tasks/local_authority_links.rake

@@ -0,0 +1,13 @@
+namespace :data_import do
+  desc "Import local authority links data"
+  task :local_authority_links, %i[path] => :environment do |_task, args|
+    path = args[:path]
+
+    raise "Usage: rake data_import:local_authority_links['path/to/csv_file']" if path.blank?
+
+    service = Imports::LocalAuthorityLinksService.new(path:)
+    service.call
+
+    pp "Created/updated #{service.count} local authority link records" unless Rails.env.test?
+  end
+end

spec/fixtures/files/local_authority_links_2023.csv

@@ -0,0 +1,6 @@
+local_authority_code,linked_local_authority_code
+E06000063,E07000027
+E06000063,E07000030
+E06000063,E07000031
+E07000027,E06000063
+E07000030,E06000063

spec/lib/tasks/local_authority_links_import_spec.rb

@@ -0,0 +1,40 @@
+require "rails_helper"
+require "rake"
+
+RSpec.describe "data_import" do
+  describe ":local_authority_links", type: :task do
+    subject(:task) { Rake::Task["data_import:local_authority_links"] }
+
+    before do
+      LocalAuthorityLink.destroy_all
+      Rake.application.rake_require("tasks/local_authority_links")
+      Rake::Task.define_task(:environment)
+      task.reenable
+    end
+
+    context "when the rake task is run" do
+      let(:local_authority_links_file_path) { "./spec/fixtures/files/local_authority_links_2023.csv" }
+      let(:wrong_file_path) { "/test/no_csv_here.csv" }
+
+      it "creates new local authority links records" do
+        expect { task.invoke(local_authority_links_file_path) }.to change(LocalAuthorityLink, :count).by(5)
+        expect(LocalAuthorityLink.where(local_authority_id: LocalAuthority.find_by(code: "E06000063").id).exists?).to be true
+      end
+
+      it "raises an error when no path is given" do
+        expect { task.invoke(nil) }.to raise_error(RuntimeError, "Usage: rake data_import:local_authority_links['path/to/csv_file']")
+      end
+
+      it "raises an error when no file exists at the given path" do
+        expect { task.invoke(wrong_file_path) }.to raise_error(Errno::ENOENT)
+      end
+
+      context "when a record already exists with a matching ids" do
+        it "does not create a new link" do
+          task.invoke(local_authority_links_file_path)
+          expect { task.invoke(local_authority_links_file_path) }.to change(LocalAuthorityLink, :count).by(0)
+        end
+      end
+    end
+  end
+end