Adds tests for the SolrDocument to boost test coverage

spec/models/solr_document_spec.rb

@@ -0,0 +1,23 @@
+require 'rails_helper'
+
+RSpec.describe SolrDocument do
+  it 'is keyed on id' do
+    expect(SolrDocument.unique_key).to eq 'id'
+  end
+
+  describe 'extensions' do
+    let(:extensions) { SolrDocument.registered_extensions.pluck :module_obj }
+
+    it 'uses the email extension' do
+      expect(extensions).to include Blacklight::Document::Email
+    end
+
+    it 'uses the sms extension' do
+      expect(extensions).to include Blacklight::Document::Sms
+    end
+
+    it 'uses the dublin core extension' do
+      expect(extensions).to include Blacklight::Document::DublinCore
+    end
+  end
+end