add simple_schema_loader spec

spec/services/spot/simple_schema_loader_spec.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+RSpec.describe Spot::SimpleSchemaLoader, valkyrization: true do
+  before(:each) do
+    # @note can't use described_class in this scope
+    class ResourceWithSchemaLoader < Hyrax::Resource
+      include Hyrax::Schema(:base_metadata, schema_loader: Spot::SimpleSchemaLoader.new)
+    end
+
+    class ResourceWithHyraxSchemaLoader < Hyrax::Resource
+      include Hyrax::Schema(:base_metadata)
+    end
+  end
+
+  after(:each) do
+    Object.send(:remove_const, :ResourceWithSchemaLoader)
+    Object.send(:remove_const, :ResourceWithHyraxSchemaLoader)
+  end
+
+  context 'when using the Hyrax schema loader' do
+    let(:resource) { ResourceWithHyraxSchemaLoader.new }
+
+    describe 'URI fields' do
+      it 'inits an RDF with a Dry::Types::Undefined value' do
+        expect(resource.send(:subject)).to eq [RDF::URI.new(Dry::Types::Undefined)]
+        expect(resource.send(:subject).map(&:to_s)).to eq ['Undefined']
+      end
+    end
+  end
+
+  context 'when using our schema loader' do
+    let(:schema_loader) { described_class.new }
+    let(:resource) { ResourceWithSchemaLoader.new }
+
+    describe 'URI fields' do
+      it 'inits no values' do
+        expect(resource.send(:subject).map(&:to_s)).to eq []
+      end
+    end
+
+    it 'wraps single-value fields in an Identity class' do
+      expect(schema_loader.attributes_for(schema: :core_metadata))
+        .to include(depositor: Spot::SimpleSchemaLoader::AttributeDefinition::Identity.of(Valkyrie::Types::String))
+    end
+  end
+end