Hide versioning UI when unsupported by adapter

app/presenters/hyrax/version_list_presenter.rb

@@ -5,17 +5,19 @@ module Hyrax
   class VersionListPresenter
     include Enumerable
 
+    attr_reader :versioning_service
+
     ##
-    # @param version_list [Array<#created>]
-    def initialize(version_list)
-      @raw_list = version_list
+    # @param service [Hyrax::VersioningService]
+    def initialize(service)
+      @versioning_service = service
     end
 
     ##
     # @param [Object] an object representing the File Set
     #
-    # @return [Enumerable<Hyrax::VersionPresenter>] an enumerable of presenters
-    #   for the relevant file versions.
+    # @return [Hyrax::VersionListPresenter] an enumerable of presenters for the
+    #   relevant file versions.
     #
     # @raise [ArgumentError] if we can't build an enu
     def self.for(file_set:)
@@ -24,18 +26,19 @@ def self.for(file_set:)
                       else
                         Hyrax::FileSetFileService.new(file_set: file_set).original_file
                       end
-      new(Hyrax::VersioningService.new(resource: original_file).versions)
+      new(Hyrax::VersioningService.new(resource: original_file))
     rescue NoMethodError
       raise ArgumentError
     end
 
-    delegate :each, to: :wrapped_list
+    delegate :each, :empty?, to: :wrapped_list
+    delegate :supports_multiple_versions?, to: :versioning_service
 
     private
 
     def wrapped_list
       @wrapped_list ||=
-        @raw_list.map { |v| Hyrax::VersionPresenter.new(v) } # wrap each item in a presenter
+        @versioning_service.versions.map { |v| Hyrax::VersionPresenter.new(v) } # wrap each item in a presenter
                  .sort { |a, b| b.version.created <=> a.version.created } # sort list of versions based on creation date
                  .tap { |l| l.first.try(:current!) } # set the first version to the current version
     end

app/views/hyrax/file_sets/_versioning.html.erb

@@ -1,6 +1,6 @@
 <div id="versioning_display" class="tab-pane">
   <h2><%= t('.header') %></h2>
-  <%= simple_form_for [main_app, curation_concern], html: { multipart: true, class: 'nav-safety' } do |f| %>
+  <% if @version_list.supports_multiple_versions? %><%= simple_form_for [main_app, curation_concern], html: { multipart: true, class: 'nav-safety' } do |f| %>
     <div id="fileuploadVersioning">
       <!-- Redirect browsers with JavaScript disabled to the origin page -->
       <noscript><input type="hidden" name="redirect" value="<%= main_app.root_path %>"/></noscript>
@@ -45,10 +45,10 @@
         <%= t('.upload') %>
       <% end %>
 
-    </div> <!-- fileuploadVersioning -->
-  <% end %>
+    </div> <!-- /fileuploadVersioning -->
+  <% end %><% end %>
 
-  <%= form_for [main_app, curation_concern],
+  <% if !@version_list.empty? %><%= form_for [main_app, curation_concern],
                html: { class: 'edit_file_set_previous_version nav-safety' } do |f| %>
     <h3><%= t('.restore') %></h3>
     <% @version_list.each do |version| %>
@@ -68,7 +68,7 @@
                  type: 'submit' do %>
       <%= t('.save') %>
     <% end %>
-  <% end %>
+  <% end %><% end %>
 
   <%= render 'hyrax/uploads/js_templates_versioning' %>
 

spec/presenters/hyrax/version_list_presenter_spec.rb

@@ -1,63 +1,77 @@
 # frozen_string_literal: true
 RSpec.describe Hyrax::VersionListPresenter do
-  let(:resource_version) do
-    ActiveFedora::VersionsGraph::ResourceVersion.new.tap do |v|
-      v.uri = 'http://example.com/version1'
-      v.label = 'version1'
-      v.created = '2014-12-09T02:03:18.296Z'
+  let(:file_set) { FactoryBot.create(:file_set) }
+  subject(:enum) { described_class.for(file_set: file_set) }
+
+  context "when the file set has no versions" do
+    describe ".for" do
+      it "returns an enumerable with no members" do
+        expect(enum.count).to eq 0
+      end
     end
-  end
 
-  let(:resource_version2) do
-    ActiveFedora::VersionsGraph::ResourceVersion.new.tap do |v|
-      v.uri = 'http://example.com/version2'
-      v.label = 'version2'
-      v.created = '2014-12-19T02:03:18.296Z'
+    describe "#each" do
+      it "yields nothing" do
+        versions_descending = []
+        enum.each do |v|
+          versions_descending.push(v.label)
+        end
+        expect(versions_descending).to be_empty
+      end
+    end
+
+    describe "#empty?" do
+      it "is true" do
+        expect(enum).to be_empty
+      end
     end
   end
 
-  subject(:enum) { described_class.new([resource_version, resource_version2]) }
+  context "when the file set has versions" do
+    before do
+      binary     = StringIO.new("hey")
+      new_binary = StringIO.new("hey2")
 
-  describe ".for" do
-    context "with an ActiveFedora::Base" do
-      it "gives an empty enumerable" do
-        file_set = FactoryBot.create(:file_set)
+      Hydra::Works::AddFileToFileSet
+        .call(file_set, binary, :original_file, versioning: true)
+      Hydra::Works::AddFileToFileSet
+        .call(file_set, new_binary, :original_file, versioning: true)
+    end
 
-        expect(described_class.for(file_set: file_set)).to be_none
+    describe ".for" do
+      it "returns an enumerable with members" do
+        expect(enum.count).to eq 2
       end
+    end
 
-      it "enumerates over version presenters for original_file" do
-        file_set   = FactoryBot.create(:file_set)
-        binary     = StringIO.new("hey")
-        new_binary = StringIO.new("hey2")
-
-        Hydra::Works::AddFileToFileSet
-          .call(file_set, binary, :original_file, versioning: true)
-        Hydra::Works::AddFileToFileSet
-          .call(file_set, new_binary, :original_file, versioning: true)
-
-        expect(described_class.for(file_set: file_set).count).to eq 2
+    describe "#each" do
+      it "yields version presenters in order" do
+        versions = Hyrax::VersioningService.new(resource: file_set.original_file).versions
+        versions_descending = []
+        enum.each do |v|
+          expect(v).to be_kind_of Hyrax::VersionPresenter
+          versions_descending.push(v.uri)
+        end
+        expect(versions_descending).to eq versions
+          .sort { |a, b| b.created <=> a.created }
+          .map(&:uri)
       end
     end
 
-    context "with a bad argument" do
-      it "raises an error" do
-        expect { described_class.for(file_set: nil) }
-          .to raise_error ArgumentError
+    describe "#empty?" do
+      it "is false" do
+        expect(enum).not_to be_empty
       end
     end
   end
 
-  describe "#each" do
-    it "yields version_presenters" do
-      versions_descending = []
+  context "when the file set is bad" do
+    let(:file_set) { nil }
 
-      enum.each do |v|
-        expect(v).to be_kind_of Hyrax::VersionPresenter
-        versions_descending.push(v.label)
+    describe ".for" do
+      it "raises an error" do
+        expect { enum }.to raise_error ArgumentError
       end
-
-      expect(versions_descending).to eq ['version2', 'version1']
     end
   end
 end

spec/views/hyrax/file_sets/_versioning.html.erb_spec.rb

@@ -1,19 +1,36 @@
 # frozen_string_literal: true
 RSpec.describe 'hyrax/file_sets/_versioning.html.erb', type: :view do
   let(:file_set) { stub_model(FileSet) }
+  let(:versioning_service) { Hyrax::VersioningService.new(resource: nil) }
 
   before do
-    allow(file_set).to receive(:files).and_return([])
     allow(view).to receive(:curation_concern).and_return(file_set)
-    assign(:version_list, [])
-    render
+    assign(:version_list, Hyrax::VersionListPresenter.new(versioning_service))
   end
 
-  context "without additional users" do
+  context "when versioning is supported" do
+    before do
+      allow(versioning_service).to receive(:supports_multiple_versions?).and_return(true)
+      allow(versioning_service).to receive(:versions).and_return([])
+      render
+    end
+
     it "draws the new version form without error" do
       expect(rendered).to have_content t("hyrax.file_sets.versioning.choose_file")
       expect(rendered).to have_content t("hyrax.uploads.js_templates_versioning.options.messages.max_file_size")
       expect(rendered).to have_content "maxFileSize: #{Hyrax.config.uploader[:maxFileSize]}"
+      expect(rendered).to have_content t("hyrax.file_sets.versioning.upload")
+    end
+  end
+
+  context "when versioning is unsupported" do
+    before do
+      allow(versioning_service).to receive(:supports_multiple_versions?).and_return(false)
+      render
+    end
+
+    it "does not draw the new version form" do
+      expect(rendered).not_to have_content t("hyrax.file_sets.versioning.upload")
     end
   end
 end