From bf0a2977fc6d5a5031c6ed745394ebf8e103b5e8 Mon Sep 17 00:00:00 2001
From: miteruzo <miteruzo@naver.com>
Date: Sun, 4 Oct 2026 14:53:40 +0900
Subject: [PATCH] =?UTF-8?q?#422=20Spec=20=E6=95=B4=E5=82=99?=
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---
 .../spec/db/tag_description_migration_spec.rb |  34 +++
 .../requests/tag_description_wiki_spec.rb     | 276 ++++++++++++++++++
 .../tag_description_wiki_write_spec.rb        | 162 ++++++++++
 .../requests/wiki_unmigrated_contract_spec.rb |  96 ++++++
 4 files changed, 568 insertions(+)
 create mode 100644 backend/spec/db/tag_description_migration_spec.rb
 create mode 100644 backend/spec/requests/tag_description_wiki_spec.rb
 create mode 100644 backend/spec/requests/tag_description_wiki_write_spec.rb
 create mode 100644 backend/spec/requests/wiki_unmigrated_contract_spec.rb

diff --git a/backend/spec/db/tag_description_migration_spec.rb b/backend/spec/db/tag_description_migration_spec.rb
new file mode 100644
index 0000000..012bd29
--- /dev/null
+++ b/backend/spec/db/tag_description_migration_spec.rb
@@ -0,0 +1,34 @@
+require 'rails_helper'
+require_relative '../../db/migrate/20261003010000_migrate_tag_descriptions_from_wiki_pages'
+
+RSpec.describe 'Tag description migration identity' do
+  it 'preserves every revision ID and repeated body in an independent sequence' do
+    user = create_member_user!
+    tag_name = create(:tag_name, name: 'description_migration')
+    page = Wiki::Commit.create_content!(
+        tag_name:, body: 'A', created_by_user: user)
+    revisions = [page.current_revision]
+    ['A', 'B', 'B', 'A'].each do |body|
+      revisions << Wiki::Commit.content!(
+          page:, body:, created_user: user, base_revision_id: revisions.last.id)
+    end
+    tag = create(:tag, primary_tag_name: tag_name)
+    legacy_state = [page.reload.attributes, revisions.map(&:attributes)]
+    expect(page.wiki_versions.count).to eq(3)
+
+    migration = MigrateTagDescriptionsFromWikiPages.new
+    migration.suppress_messages { migration.up }
+
+    versions = TagDescriptionVersion.where(tag_id: tag.id, language_code: 'ja')
+        .order(:version_no)
+    expect(versions.pluck(:id)).to eq(revisions.map(&:id))
+    expect(versions.pluck(:version_no)).to eq([1, 2, 3, 4, 5])
+    expect(versions.pluck(:body)).to eq(['A', 'A', 'B', 'B', 'A'])
+    expect(versions.pluck(:created_by_user_id)).to eq([user.id] * 5)
+    expect(versions.pluck(:created_at)).to eq(revisions.map(&:created_at))
+    expect(TagDescription.find(page.id)).to have_attributes(
+        tag_id: tag.id, language_code: 'ja', version_no: 5, body: 'A')
+    expect([page.reload.attributes, revisions.map { |revision| revision.reload.attributes }])
+        .to eq(legacy_state)
+  end
+end
diff --git a/backend/spec/requests/tag_description_wiki_spec.rb b/backend/spec/requests/tag_description_wiki_spec.rb
new file mode 100644
index 0000000..3b9b192
--- /dev/null
+++ b/backend/spec/requests/tag_description_wiki_spec.rb
@@ -0,0 +1,276 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag description Wiki compatibility', type: :request do
+  let!(:user) { create_member_user! }
+  let!(:tag_name) { create(:tag_name, name: 'description_contract') }
+  let!(:page) do
+    Wiki::Commit.create_content!(
+        tag_name:, body: 'old-revision', created_by_user: user)
+  end
+  let!(:revisions) do
+    first = page.current_revision
+    second = Wiki::Commit.content!(page:, body: 'old-second', created_user: user)
+    third = Wiki::Commit.content!(page:, body: 'old-third', created_user: user)
+    [first, second, third]
+  end
+  let!(:tag) { create(:tag, primary_tag_name: tag_name) }
+  let!(:versions) do
+    revisions.each_with_index.map do |revision, index|
+      TagDescriptionVersion.create!(
+          id: revision.id, tag_id: tag.id, language_code: 'ja',
+          version_no: index + 1, event_type: index.zero? ? 'create' : 'update',
+          body: index == 2 ? 'new-version' : 'A',
+          created_by_user_id: user.id, created_at: revision.created_at)
+    end
+  end
+  let!(:description) do
+    TagDescription.create!(
+        id: page.id, tag:, language_code: 'ja', version_no: 3, body: 'new',
+        created_by_user_id: user.id, updated_by_user_id: user.id)
+  end
+
+  before { page.update_columns(body: 'old') }
+
+  # Observe real SELECTs, including cached queries, only during the request.
+  def without_legacy_reads
+    queries = []
+    subscriber = lambda do |*args|
+      sql = args.last.fetch(:sql)
+      if sql.match?(/\bSELECT\b/i) && sql.match?(/\bwiki_(pages|revisions|versions)\b/i)
+        queries << sql
+      end
+    end
+    ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') { yield }
+    expect(queries).to be_empty
+  end
+
+  describe 'show' do
+    it 'uses current content and revision identity without legacy reads' do
+      without_legacy_reads { get "/wiki/#{ description.id }" }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('body' => 'new', 'revision_id' => versions.last.id,
+                             'pred' => versions.second.id, 'succ' => nil)
+    end
+
+    [0, 1, 2].each do |index|
+      it "navigates displayed version #{ index + 1 }, preserving repeated bodies" do
+        without_legacy_reads do
+          get "/wiki/#{ description.id }", params: { version: versions[index].id }
+        end
+        expect(response).to have_http_status(:ok)
+        expect(json).to include(
+            'body' => index == 2 ? 'new' : 'A',
+            'revision_id' => versions[index].id,
+            'pred' => index.zero? ? nil : versions[index - 1].id,
+            'succ' => index == 2 ? nil : versions[index + 1].id)
+      end
+    end
+
+    it 'does not fall back to a revision absent from new history' do
+      versions.first.destroy!
+      without_legacy_reads do
+        get "/wiki/#{ description.id }", params: { version: revisions.first.id }
+      end
+      expect(response).to have_http_status(:not_found)
+    end
+
+    it 'does not fall back when the new current revision is missing' do
+      versions.last.destroy!
+      without_legacy_reads { get "/wiki/#{ description.id }" }
+      expect(response).to have_http_status(:not_found)
+    end
+  end
+
+  describe 'revision resource scope' do
+    let!(:other_tag) { create(:tag, primary_name: 'other_description_contract') }
+    let!(:other_version) do
+      TagDescriptionVersion.create!(
+          tag_id: other_tag.id, language_code: 'ja', version_no: 1,
+          event_type: 'create', body: 'other tag history',
+          created_by_user_id: user.id, created_at: Time.current)
+    end
+    let!(:other_description) do
+      TagDescription.create!(
+          tag: other_tag, language_code: 'ja', version_no: 1, body: 'other tag history',
+          created_by_user_id: user.id, updated_by_user_id: user.id)
+    end
+
+    it 'returns 404 when show specifies another tag description version' do
+      get "/wiki/#{ description.id }", params: { version: other_version.id }
+      expect(response).to have_http_status(:not_found)
+      expect(response.body).not_to include(other_version.body)
+    end
+
+    it 'returns 404 when diff from belongs to another tag description' do
+      get "/wiki/#{ description.id }/diff",
+          params: { from: other_version.id, to: versions.last.id }
+      expect(response).to have_http_status(:not_found)
+      expect(response.body).not_to include(other_version.body)
+    end
+
+    it 'returns 404 when diff to belongs to another tag description' do
+      get "/wiki/#{ description.id }/diff",
+          params: { from: versions.first.id, to: other_version.id }
+      expect(response).to have_http_status(:not_found)
+      expect(response.body).not_to include(other_version.body)
+    end
+  end
+
+  describe 'show_by_title' do
+    it 'resolves TagName and reads current content from new tables' do
+      without_legacy_reads { get "/wiki/title/#{ tag_name.name }" }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('id' => description.id, 'body' => 'new',
+                             'revision_id' => versions.last.id)
+    end
+
+    it 'uses historical content and navigation from the new history' do
+      get "/wiki/title/#{ tag_name.name }", params: { version: versions.second.id }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include('body' => 'A', 'revision_id' => versions.second.id,
+                             'pred' => versions.first.id, 'succ' => versions.last.id)
+    end
+
+    it 'ignores changes to same-title legacy content and revision metadata' do
+      get "/wiki/title/#{ tag_name.name }"
+      original = json
+      page.update_columns(body: 'changed legacy body')
+      revisions.last.update_columns(message: 'legacy message', created_at: 1.day.ago)
+      revisions.last.wiki_lines.update_all(body: 'changed legacy revision')
+      get "/wiki/title/#{ tag_name.name }"
+      expect(json).to eq(original)
+      expect(json.fetch('body')).to eq('new')
+    end
+  end
+
+  describe 'exists' do
+    it 'recognises an ID without reading legacy tables' do
+      without_legacy_reads { get "/wiki/#{ description.id }/exists" }
+      expect(response).to have_http_status(:no_content)
+    end
+
+    it 'recognises a title without reading legacy tables' do
+      without_legacy_reads { get "/wiki/title/#{ tag_name.name }/exists" }
+      expect(response).to have_http_status(:no_content)
+    end
+
+    context 'without a legacy page' do
+      before do
+        WikiVersion.where(wiki_page_id: page.id).delete_all
+        page.destroy!
+      end
+
+      it 'recognises the description ID alone' do
+        get "/wiki/#{ description.id }/exists"
+        expect(response).to have_http_status(:no_content)
+      end
+
+      it 'recognises the TagName alone' do
+        get "/wiki/title/#{ tag_name.name }/exists"
+        expect(response).to have_http_status(:no_content)
+      end
+
+      it 'shows the description by title' do
+        get "/wiki/title/#{ tag_name.name }"
+        expect(response).to have_http_status(:ok)
+        expect(json).to include('body' => 'new', 'revision_id' => versions.last.id)
+      end
+    end
+  end
+
+  describe 'diff' do
+    [false, true].each do |current|
+      it "uses new bodies with #{ current ? 'implicit current' : 'explicit to' }" do
+        params = { from: versions.first.id }
+        params[:to] = versions.last.id unless current
+        get "/wiki/#{ description.id }/diff", params: params
+        expect(response).to have_http_status(:ok)
+        expect(json).to include(
+            'wiki_page_id' => description.id,
+            'older_revision_id' => versions.first.id,
+            'newer_revision_id' => versions.last.id,
+            'diff' => [{ 'type' => 'removed', 'content' => 'A' },
+                       { 'type' => 'added', 'content' => 'new-version' }])
+      end
+    end
+
+    it 'does not query legacy tables for diff' do
+      without_legacy_reads do
+        get "/wiki/#{ description.id }/diff",
+            params: { from: versions.first.id, to: versions.last.id }
+      end
+      expect(response).to have_http_status(:ok)
+    end
+
+    it 'keeps distinct revision IDs for identical consecutive bodies' do
+      get "/wiki/#{ description.id }/diff",
+          params: { from: versions.first.id, to: versions.second.id }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'older_revision_id' => versions.first.id,
+          'newer_revision_id' => versions.second.id,
+          'diff' => [{ 'type' => 'context', 'content' => 'A' }])
+    end
+  end
+
+  describe 'changes' do
+    it 'lists every new version including consecutive identical bodies' do
+      without_legacy_reads { get '/wiki/changes', params: { id: description.id } }
+      expect(response).to have_http_status(:ok)
+      expect(json.map { |row| row.fetch('revision_id') }).to eq(versions.reverse.map(&:id))
+      expect(json.first.keys).to match_array(
+          ['revision_id', 'pred', 'succ', 'wiki_page', 'user', 'kind', 'message', 'timestamp'])
+      expect(json.first).to include(
+          'pred' => versions.second.id, 'succ' => nil, 'kind' => 'content',
+          'timestamp' => versions.last.created_at.iso8601(3),
+          'user' => { 'id' => user.id, 'name' => user.name })
+      expect(json.first.fetch('wiki_page')).to include('id' => description.id,
+                                                      'title' => tag_name.name)
+    end
+
+    it 'ignores legacy-only revisions and metadata changes' do
+      get '/wiki/changes', params: { id: description.id }
+      original = json
+      revisions.first.update_columns(message: 'legacy changed', created_at: 1.day.ago)
+      WikiRevision.create!(
+          wiki_page: page, created_user: user, kind: :content,
+          tree_sha256: Digest::SHA256.hexdigest('legacy only'), lines_count: 0)
+      get '/wiki/changes', params: { id: description.id }
+      expect(json).to eq(original)
+      expect(json.map { |row| row.fetch('revision_id') }).to eq(versions.reverse.map(&:id))
+    end
+  end
+
+  describe 'mixed changes' do
+    it 'includes unmigrated history and ignores migrated legacy-only revisions' do
+      legacy_page = Wiki::Commit.create_content!(
+          tag_name: create(:tag_name, name: 'Help_mixed'),
+          body: 'help', created_by_user: user)
+      legacy_revision = legacy_page.current_revision
+      extra = WikiRevision.create!(
+          wiki_page: page, created_user: user, kind: :content,
+          tree_sha256: Digest::SHA256.hexdigest('legacy only'), lines_count: 0)
+
+      get '/wiki/changes'
+      expect(response).to have_http_status(:ok)
+      migrated = json.select { |row| row.fetch('wiki_page').fetch('id') == description.id }
+      expect(migrated.map { |row| row.fetch('revision_id') }).to eq(versions.reverse.map(&:id))
+      expect(json.map { |row| row.fetch('revision_id') }).not_to include(extra.id)
+      expect(json).to include(include(
+          'revision_id' => legacy_revision.id,
+          'wiki_page' => include('id' => legacy_page.id, 'title' => 'Help_mixed')))
+    end
+  end
+
+  describe 'index' do
+    [nil, 'description_contract'].each do |title|
+      it "returns new content once in #{ title ? 'filtered' : 'unfiltered' } index" do
+        get '/wiki', params: { title: }
+        expect(response).to have_http_status(:ok)
+        rows = json.select { |row| row.fetch('id') == description.id }
+        expect(rows.size).to eq(1)
+        expect(rows.first).to include('body' => 'new', 'title' => tag_name.name)
+      end
+    end
+  end
+end
diff --git a/backend/spec/requests/tag_description_wiki_write_spec.rb b/backend/spec/requests/tag_description_wiki_write_spec.rb
new file mode 100644
index 0000000..6d83347
--- /dev/null
+++ b/backend/spec/requests/tag_description_wiki_write_spec.rb
@@ -0,0 +1,162 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag description Wiki dual writes', type: :request do
+  let!(:user) { create_member_user! }
+  let!(:tag_name) { create(:tag_name, name: 'description_write') }
+  let(:tag) { create(:tag, primary_tag_name: tag_name) }
+  let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+
+  def stored_state
+    [WikiPage, WikiRevision, WikiVersion, TagDescription, TagDescriptionVersion,
+     TagName, TagVersion].map do |model|
+      model.order(:id).map(&:attributes)
+    end
+  end
+
+  # Fail after a real INSERT/UPDATE, exercising rollback rather than a mock write.
+  def fail_save model
+    failure = Class.new(StandardError)
+    callback = ->(_record) { raise failure, 'injected persistence failure' }
+    model.set_callback(:save, :after, callback)
+    expect { yield }.to raise_error(failure)
+  ensure
+    model.skip_callback(:save, :after, callback)
+  end
+
+  describe 'POST /wiki' do
+    before { tag }
+
+    def create_description
+      post '/wiki', params: { title: tag_name.name, body: 'initial', message: 'create' },
+           headers: headers
+    end
+
+    it 'creates both current records and histories with a shared revision ID' do
+      expect { create_description }
+          .to change(WikiPage, :count).by(1)
+          .and change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+          .and change(TagDescription, :count).by(1)
+          .and change(TagDescriptionVersion, :count).by(1)
+      expect(response).to have_http_status(:created)
+
+      page = WikiPage.find(json.fetch('id'))
+      description = TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
+      version = TagDescriptionVersion.find_by!(tag_id: tag.id, language_code: 'ja')
+      expect(description).to have_attributes(id: page.id, body: 'initial', version_no: 1)
+      expect(version).to have_attributes(
+          id: page.current_revision.id, body: 'initial', version_no: 1,
+          event_type: 'create', created_by_user_id: user.id)
+      expect(page.body).to eq(description.body)
+      expect(page.current_revision.body).to eq(version.body)
+      expect(page.wiki_versions.last.body).to eq(version.body)
+    end
+
+    [WikiPage, WikiRevision, WikiVersion, TagDescription, TagDescriptionVersion].each do |model|
+      it "rolls back both systems when #{ model.name } persistence fails" do
+        tag_name
+        before_state = stored_state
+        aggregate_failures do
+          fail_save(model) { create_description }
+          expect(stored_state).to eq(before_state)
+        end
+      end
+    end
+  end
+
+  describe 'PUT /wiki/:id' do
+    let!(:page) do
+      Wiki::Commit.create_content!(
+          tag_name:, body: 'before', created_by_user: user)
+    end
+    let!(:first_revision) { page.current_revision }
+    let!(:current_revision) do
+      # Repeated bodies create revisions, but no extra WikiVersion snapshot.
+      Wiki::Commit.content!(page:, body: 'before', created_user: user,
+                            base_revision_id: first_revision.id)
+    end
+    let!(:description) do
+      TagDescription.create!(
+          id: page.id, tag:, language_code: 'ja', body: 'before', version_no: 2,
+          created_by_user_id: user.id, updated_by_user_id: user.id)
+    end
+
+    before do
+      [first_revision, current_revision].each_with_index do |revision, index|
+        TagDescriptionVersion.create!(
+            id: revision.id, tag_id: tag.id, language_code: 'ja', version_no: index + 1,
+            body: 'before', event_type: index.zero? ? 'create' : 'update',
+            created_by_user_id: user.id, created_at: revision.created_at)
+      end
+    end
+
+    def update_description body: 'after', title: tag_name.name, base: current_revision.id
+      put "/wiki/#{ page.id }",
+          params: { title:, body:, message: 'edit', base_revision_id: base },
+          headers: headers
+    end
+
+    it 'increments the independent description sequence and shares revision identity' do
+      expect(page.reload.version_no).to eq(1)
+      expect(description.version_no).to eq(2)
+      expect { update_description }
+          .to change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+          .and change(TagDescriptionVersion, :count).by(1)
+      expect(response).to have_http_status(:ok)
+
+      revision = page.reload.current_revision
+      version = TagDescriptionVersion.find(revision.id)
+      expect(description.reload).to have_attributes(body: 'after', version_no: 3)
+      expect(version).to have_attributes(
+          body: 'after', version_no: 3, event_type: 'update', created_by_user_id: user.id)
+      expect(page).to have_attributes(body: 'after', version_no: 2)
+      expect(revision.body).to eq(version.body)
+      expect(page.wiki_versions.order(:version_no).last.body).to eq(version.body)
+    end
+
+    it 'mirrors the Wiki revision for a title-only update despite identical bodies' do
+      expect { update_description(body: 'before', title: 'description_renamed') }
+          .to change(WikiRevision, :count).by(1)
+          .and change(TagDescriptionVersion, :count).by(1)
+      expect(response).to have_http_status(:ok)
+      expect(tag_name.reload.name).to eq('description_renamed')
+      expect(description.reload).to have_attributes(body: 'before', version_no: 3)
+
+      revision = page.reload.current_revision
+      version = TagDescriptionVersion.find(revision.id)
+      expect(revision.body).to eq('before')
+      expect(version).to have_attributes(
+          tag_id: tag.id, language_code: 'ja', body: 'before', version_no: 3,
+          event_type: 'update', created_by_user_id: user.id)
+      expect(TagDescriptionVersion.where(tag_id: tag.id, language_code: 'ja').order(:id).ids)
+          .to eq(page.wiki_revisions.order(:id).ids)
+    end
+
+    it 'does not add a description version for a TagName rename through tags' do
+      expect do
+        patch "/tags/#{ tag.id }", params: { name: 'description_tag_renamed' }, headers: headers
+      end.not_to change(TagDescriptionVersion, :count)
+      expect(response).to have_http_status(:ok)
+      expect(tag_name.reload.name).to eq('description_tag_renamed')
+      expect(description.reload).to have_attributes(body: 'before', version_no: 2)
+    end
+
+    it 'keeps both systems and the title unchanged on a stale revision conflict' do
+      before_state = stored_state
+      update_description(title: 'conflicting_rename', base: first_revision.id)
+      expect(response).to have_http_status(:conflict)
+      expect(stored_state).to eq(before_state)
+    end
+
+    [WikiPage, WikiRevision, WikiVersion, TagDescription, TagDescriptionVersion].each do |model|
+      it "rolls back both systems when #{ model.name } persistence fails" do
+        before_state = stored_state
+        aggregate_failures do
+          fail_save(model) { update_description(title: 'rollback_rename') }
+          expect(stored_state).to eq(before_state)
+        end
+      end
+    end
+  end
+end
diff --git a/backend/spec/requests/wiki_unmigrated_contract_spec.rb b/backend/spec/requests/wiki_unmigrated_contract_spec.rb
new file mode 100644
index 0000000..1029b0f
--- /dev/null
+++ b/backend/spec/requests/wiki_unmigrated_contract_spec.rb
@@ -0,0 +1,96 @@
+require 'rails_helper'
+
+RSpec.describe 'Unmigrated Wiki compatibility', type: :request do
+  let!(:user) { create_member_user! }
+  let!(:tag_name) { create(:tag_name, name: 'Help_contract') }
+  let!(:page) do
+    Wiki::Commit.create_content!(tag_name:, body: 'before', created_by_user: user)
+  end
+  let!(:first_revision) { page.current_revision }
+  let!(:last_revision) do
+    Wiki::Commit.content!(page:, body: 'after', created_user: user,
+                          message: 'legacy edit', base_revision_id: first_revision.id)
+  end
+
+  before { expect(TagDescription.exists?(id: page.id)).to be(false) }
+
+  it 'shows legacy current and historical content by ID' do
+    get "/wiki/#{ page.id }"
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('body' => 'after', 'revision_id' => last_revision.id,
+                           'pred' => first_revision.id, 'succ' => nil)
+    get "/wiki/#{ page.id }", params: { version: first_revision.id }
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('body' => 'before', 'revision_id' => first_revision.id,
+                           'pred' => nil, 'succ' => last_revision.id)
+  end
+
+  it 'shows legacy current and historical content by title' do
+    get "/wiki/title/#{ tag_name.name }"
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('body' => 'after', 'revision_id' => last_revision.id)
+    get "/wiki/title/#{ tag_name.name }", params: { version: first_revision.id }
+    expect(response).to have_http_status(:ok)
+    expect(json).to include('body' => 'before', 'revision_id' => first_revision.id)
+  end
+
+  it 'recognises legacy IDs' do
+    get "/wiki/#{ page.id }/exists"
+    expect(response).to have_http_status(:no_content)
+  end
+
+  it 'recognises legacy titles' do
+    get "/wiki/title/#{ tag_name.name }/exists"
+    expect(response).to have_http_status(:no_content)
+  end
+
+  it 'diffs legacy revisions with explicit and current target' do
+    [last_revision.id, nil].each do |to|
+      get "/wiki/#{ page.id }/diff", params: { from: first_revision.id, to: }
+      expect(response).to have_http_status(:ok)
+      expect(json).to include(
+          'wiki_page_id' => page.id, 'title' => tag_name.name,
+          'older_revision_id' => first_revision.id, 'newer_revision_id' => last_revision.id,
+          'diff' => [{ 'type' => 'removed', 'content' => 'before' },
+                     { 'type' => 'added', 'content' => 'after' }])
+    end
+  end
+
+  describe 'revision resource scope' do
+    let!(:other_page) do
+      Wiki::Commit.create_content!(
+          tag_name: create(:tag_name, name: 'Help_other_contract'),
+          body: 'other page history', created_by_user: user)
+    end
+    let(:other_revision) { other_page.current_revision }
+
+    it 'returns 404 when show specifies another page revision' do
+      get "/wiki/#{ page.id }", params: { version: other_revision.id }
+      expect(response).to have_http_status(:not_found)
+    end
+
+    it 'returns 404 when diff from belongs to another page' do
+      get "/wiki/#{ page.id }/diff",
+          params: { from: other_revision.id, to: last_revision.id }
+      expect(response).to have_http_status(:not_found)
+    end
+
+    it 'returns 404 when diff to belongs to another page' do
+      get "/wiki/#{ page.id }/diff",
+          params: { from: first_revision.id, to: other_revision.id }
+      expect(response).to have_http_status(:not_found)
+    end
+  end
+
+  it 'retains legacy history metadata and ordering' do
+    get '/wiki/changes', params: { id: page.id }
+    expect(response).to have_http_status(:ok)
+    expect(json.map { |row| row.fetch('revision_id') }).to eq(
+        [last_revision.id, first_revision.id])
+    expect(json.first).to include(
+        'pred' => first_revision.id, 'succ' => nil, 'kind' => 'content',
+        'message' => 'legacy edit', 'timestamp' => last_revision.created_at.iso8601(3),
+        'wiki_page' => { 'id' => page.id, 'title' => tag_name.name, 'deprecated_at' => nil },
+        'user' => { 'id' => user.id, 'name' => user.name })
+  end
+end