Hide details if there is no change history

Sometimes change history can be present, but doesn’t have items within
it. To get around this, we move the logic to the component and only
render the details if there are any details rendered.

Additionally, I’ve changed the version factory to build, rather than
create so we don’t have to create versions in the database
unneccessarily

lib/engines/content_block_manager/app/components/content_block_manager/content_block/document/show/document_timeline/timeline_item_component.html.erb

@@ -12,25 +12,15 @@
     <%= date %>
   </p>
 
-  <% if version.field_diffs.present? %>
+  <%= version.field_diffs %>
+
+  <% if details_of_changes.present? %>
     <div class="timeline__diff-table">
       <%= render "govuk_publishing_components/components/details", {
         title: "Details of changes",
         open: is_latest,
       } do %>
-        <% capture do %>
-          <%= render ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::FieldChangesTableComponent.new(
-            version:,
-            schema:,
-            ) %>
-
-          <% embedded_object_diffs.each do |item| %>
-            <%= render ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::EmbeddedObject::FieldChangesTableComponent.new(
-              **item,
-              content_block_edition: version.item,
-              ) %>
-          <% end %>
-        <% end %>
+        <% details_of_changes %>
       <% end %>
     </div>
   <% end %>

lib/engines/content_block_manager/app/components/content_block_manager/content_block/document/show/document_timeline/timeline_item_component.rb

@@ -51,4 +51,31 @@ def embedded_object_diffs
       end
     }.flatten
   end
+
+  def details_of_changes
+    @details_of_changes ||= begin
+      return "" if version.field_diffs.blank?
+
+      [
+        main_object_field_changes,
+        embedded_object_field_changes,
+      ].join.html_safe
+    end
+  end
+
+  def main_object_field_changes
+    render ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::FieldChangesTableComponent.new(
+      version:,
+      schema:,
+    )
+  end
+
+  def embedded_object_field_changes
+    embedded_object_diffs.map do |item|
+      render ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::EmbeddedObject::FieldChangesTableComponent.new(
+        **item,
+        content_block_edition: version.item,
+      )
+    end
+  end
 end

lib/engines/content_block_manager/test/components/content_block/document/show/document_timeline/timeline_item_component_test.rb

@@ -110,7 +110,7 @@ class ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::Timel
   describe "when field diffs are present" do
     let(:field_diffs) { { "foo" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "previous value", new_value: "new value") } }
     let(:version) do
-      build(
+      build_stubbed(
         :content_block_version,
         event: "created",
         whodunnit: user.id,
@@ -121,27 +121,32 @@ class ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::Timel
       )
     end
 
-    it "renders the table component" do
-      table_component = ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::FieldChangesTableComponent.new(
-        version: build(:content_block_version, field_diffs: []),
+    let!(:table_component) do
+      ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::FieldChangesTableComponent.new(
+        version:,
         schema:,
       )
+    end
 
+    before do
       ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::FieldChangesTableComponent
         .expects(:new)
         .with(version:, schema:)
         .returns(table_component)
 
       component
         .expects(:render)
-        .with("govuk_publishing_components/components/details", { title: "Details of changes", open: false })
-        .with_block_given
-        .yields
+        .with(table_component)
+        .once
+        .returns("TABLE COMPONENT")
+    end
 
+    it "renders the table component unopened" do
       component
         .expects(:render)
-        .with(table_component)
-        .once
+        .with("govuk_publishing_components/components/details", { title: "Details of changes", open: false })
+        .with_block_given
+        .yields
 
       render_inline component
     end
@@ -157,70 +162,72 @@ class ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::Timel
         render_inline component
       end
     end
+  end
 
-    describe "when a field diff is for an embedded object" do
-      let(:subschema) { stub(:subschema, id: "embedded_schema") }
-      let(:schema) { stub(:schema, subschemas: [subschema]) }
+  describe "when a field diff is for an embedded object" do
+    let(:subschema) { stub(:subschema, id: "embedded_schema") }
+    let(:schema) { stub(:schema, subschemas: [subschema]) }
 
-      let(:field_diffs) do
-        {
-          "details" => {
-            "embedded_schema" => {
-              "something" => {
-                "field1" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
-                "field2" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
-              },
+    let(:field_diffs) do
+      {
+        "details" => {
+          "embedded_schema" => {
+            "something" => {
+              "field1" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
+              "field2" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
             },
           },
-        }
-      end
+        },
+      }
+    end
 
-      let(:version) do
-        build(
-          :content_block_version,
-          event: "created",
-          whodunnit: user.id,
-          state: "published",
-          created_at: 4.days.ago,
-          item: content_block_edition,
-          field_diffs:,
-        )
-      end
+    let(:version) do
+      build_stubbed(
+        :content_block_version,
+        event: "created",
+        whodunnit: user.id,
+        state: "published",
+        created_at: 4.days.ago,
+        item: content_block_edition,
+        field_diffs:,
+      )
+    end
 
-      it "renders the embedded table component" do
-        table_component = stub("table_component")
+    it "renders the embedded table component" do
+      table_component = stub("table_component")
 
-        ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::EmbeddedObject::FieldChangesTableComponent
-          .expects(:new)
-          .with(
-            object_id: "something",
-            field_diff: {
-              "field1" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
-              "field2" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
-            },
-            subschema_id: "embedded_schema",
-            content_block_edition:,
-          )
-          .returns(table_component)
+      ContentBlockManager::ContentBlock::Document::Show::DocumentTimeline::EmbeddedObject::FieldChangesTableComponent
+        .expects(:new)
+        .with(
+          object_id: "something",
+          field_diff: {
+            "field1" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
+            "field2" => ContentBlockManager::ContentBlock::DiffItem.new(previous_value: "before", new_value: "after"),
+          },
+          subschema_id: "embedded_schema",
+          content_block_edition:,
+        )
+        .returns(table_component)
 
-        component
-          .expects(:render)
-          .with("govuk_publishing_components/components/details", { title: "Details of changes", open: false })
-          .with_block_given
-          .yields
+      component
+        .expects(:render)
+        .with("govuk_publishing_components/components/details", { title: "Details of changes", open: false })
+        .with_block_given
+        .yields
 
-        component
-          .expects(:render)
-          .with(table_component)
-          .once
+      component
+        .expects(:render)
+        .with(table_component)
+        .once
+        .returns("TABLE COMPONENT 1")
 
-        component
-          .expects(:render)
-          .with(anything)
-          .once
+      component
+        .expects(:render)
+        .with(anything)
+        .once
+        .returns("TABLE COMPONENT 2")
 
-        render_inline component
-      end
+      render_inline component
     end
   end
 end

lib/engines/content_block_manager/test/factories/content_block_version.rb

@@ -2,15 +2,15 @@
   factory :content_block_version, class: "ContentBlockManager::ContentBlock::Version" do
     event { "created" }
     item do
-      create(
+      build(
         :content_block_edition,
-        document: create(
+        document: build(
           :content_block_document,
           block_type: "email_address",
         ),
       )
     end
-    whodunnit { create(:user).id }
+    whodunnit { build(:user).id }
     state {}
   end
 end