Test Hyrax::WorkFormService

These tests are being introduced to provide a baseline for a form service for
creating forms that work with valkyrie models.

app/services/hyrax/work_form_service.rb

@@ -1,4 +1,6 @@
 module Hyrax
+  ##
+  # A factory that builds work forms based on the `#model_name` of the work.
   class WorkFormService
     def self.build(curation_concern, current_ability, *extra)
       form_class(curation_concern).new(curation_concern, current_ability, *extra)

spec/services/hyrax/work_form_service_spec.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+RSpec.describe Hyrax::WorkFormService do
+  subject(:form_service) { described_class }
+  let(:work)             { GenericWork.new }
+
+  describe '.form_class' do
+    it 'returns a form class by constant name convention' do
+      expect(form_service.form_class(work)).to eq Hyrax::GenericWorkForm
+    end
+
+    context 'with a missing form class' do
+      let(:work) { Hyrax::Test::SimpleWorkLegacy.new }
+
+      it 'raises a NameError' do
+        expect { form_service.form_class(work) }.to raise_error NameError
+      end
+    end
+  end
+
+  describe '.build' do
+    let(:ability)    { :FAKE_ABILITY }
+    let(:controller) { :FAKE_CONTROLLER }
+
+    it 'returns an instance of the form class' do
+      expect(form_service.build(work, ability, controller))
+        .to be_a Hyrax::GenericWorkForm
+    end
+  end
+end