Connect designs-at-versions to design-collections

This mounts the new resolvers on the design collection type

ee/app/graphql/types/design_management/design_collection_type.rb

@@ -12,14 +12,32 @@ module Types
             description: 'Project associated with the design collection'
       field :issue, Types::IssueType, null: false,
             description: 'Issue associated with the design collection'
-      field :designs, Types::DesignManagement::DesignType.connection_type, null: false,
+
+      field :designs,
+            Types::DesignManagement::DesignType.connection_type,
+            null: false,
             resolver: Resolvers::DesignManagement::DesignsResolver,
             description: 'All designs for the design collection'
-      # TODO: allow getting a single design by filename
-      # exposing all designs
-      field :versions, Types::DesignManagement::VersionType.connection_type,
+
+      field :versions,
+            Types::DesignManagement::VersionType.connection_type,
             resolver: Resolvers::DesignManagement::VersionsResolver,
             description: 'All versions related to all designs, ordered newest first'
+
+      field :version,
+            Types::DesignManagement::VersionType,
+            resolver: Resolvers::DesignManagement::VersionsResolver.single,
+            description: 'A specific version'
+
+      field :design_at_version, ::Types::DesignManagement::DesignAtVersionType,
+            null: true,
+            resolver: ::Resolvers::DesignManagement::DesignAtVersionResolver,
+            description: 'Find a design as of a version'
+
+      field :design, ::Types::DesignManagement::DesignType,
+            null: true,
+            resolver: ::Resolvers::DesignManagement::DesignResolver,
+            description: 'Find a specific design'
     end
   end
 end

ee/spec/graphql/types/design_management/design_collection_type_spec.rb

@@ -5,5 +5,9 @@ require 'spec_helper'
 describe GitlabSchema.types['DesignCollection'] do
   it { expect(described_class).to require_graphql_authorizations(:read_design) }
 
-  it { expect(described_class).to have_graphql_fields(:project, :issue, :designs, :versions) }
+  it 'has the expected fields' do
+    expected_fields = %i[project issue designs versions version designAtVersion design]
+
+    expect(described_class).to have_graphql_fields(*expected_fields)
+  end
 end

ee/spec/graphql/types/design_management/version_type_spec.rb

@@ -3,11 +3,11 @@
 require 'spec_helper'
 
 describe GitlabSchema.types['DesignVersion'] do
-  let(:expected_fields) do
-    %i[id sha designs design_at_version designs_at_version]
-  end
-
   it { expect(described_class).to require_graphql_authorizations(:read_design) }
 
-  it { expect(described_class).to have_graphql_fields(*expected_fields) }
+  it 'has the expected fields' do
+    expected_fields = %i[id sha designs design_at_version designs_at_version]
+
+    expect(described_class).to have_graphql_fields(*expected_fields)
+  end
 end