Wiki 依存の排除 (#431) (#432)

Reviewed-on: #432
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/db/wiki_removal_spec.rb

@@ -0,0 +1,23 @@
+require 'rails_helper'
+
+RSpec.describe 'Schema after Wiki removal' do
+  it 'has no legacy Wiki tables or name indirection columns' do
+    connection = ApplicationRecord.connection
+    ['wiki_pages', 'wiki_revisions', 'wiki_lines', 'wiki_revision_lines', 'wiki_versions']
+        .each do |table|
+      expect(connection.table_exists?(table)).to be(false)
+    end
+    expect(connection.column_exists?(:tags, :tag_name_id)).to be(false)
+    expect(connection.column_exists?(:tag_names, :canonical_id)).to be(false)
+  end
+
+  it 'requires TagName ownership while keeping the native resources and history' do
+    connection = ApplicationRecord.connection
+    expect(TagName.columns_hash.fetch('tag_id').null).to be(false)
+    expect(connection.foreign_key_exists?(:tag_names, :tags)).to be(true)
+    ['tag_descriptions', 'tag_description_versions', 'tag_groups', 'tag_group_versions']
+        .each do |table|
+      expect(connection.table_exists?(table)).to be(true)
+    end
+  end
+end