Do not add facet limit unless it is known.

This commit updates the code that adds facet limits from user supplied
parameters so that facets are only added if they have been configured
as facet fields.  This is done to allow for multiple faceted searches to
be defined in the same URL while still keeping the facets separate.

app/helpers/blacklight/render_constraints_helper_behavior.rb

@@ -85,6 +85,8 @@ def render_filter_element(facet, values, path)
 
     safe_join(Array(values).map do |val|
       next if val.blank? # skip empty string
+      # skip if facet field not configured
+      next if blacklight_config.facet_fields[facet.to_s].blank?
       render_constraint_element(facet_field_label(facet_config.key),
                                 facet_display_value(facet, val),
                                 remove: search_action_path(path.remove_facet_params(facet, val)),

lib/blacklight/solr/search_builder_behavior.rb

@@ -95,6 +95,7 @@ def add_facet_fq_to_solr(solr_parameters)
         f_request_params = blacklight_params[:f]
 
         f_request_params.each_pair do |facet_field, value_list|
+          next unless blacklight_config.facet_fields[facet_field.to_s].present?
           Array(value_list).reject(&:blank?).each do |value|
             solr_parameters.append_filter_query facet_value_to_fq_string(facet_field, value)
           end

spec/helpers/blacklight/render_constraints_helper_behavior_spec.rb

@@ -48,13 +48,13 @@
 
     before do
       allow(helper).to receive(:blacklight_config).and_return(config)
-      expect(helper).to receive(:facet_field_label).with('type').and_return("Item Type")
     end
 
     let(:params) { ActionController::Parameters.new q: 'biz' }
     let(:path) { Blacklight::SearchState.new(params, config, controller) }
 
     it "has a link relative to the current url" do
+      expect(helper).to receive(:facet_field_label).with('type').and_return("Item Type")
       expect(subject).to have_link "Remove constraint Item Type: journal", href: "/catalog?q=biz"
       expect(subject).to have_selector ".filter-name", text: 'Item Type'
     end
@@ -63,9 +63,18 @@
       subject { helper.render_filter_element('type', 'journal', path) }
 
       it "handles string values gracefully" do
+        expect(helper).to receive(:facet_field_label).with('type').and_return("Item Type")
         expect(subject).to have_link "Remove constraint Item Type: journal", href: "/catalog?q=biz"
       end
     end
+
+    context "with unknown facet field in param" do
+      subject { helper.render_filter_element('unknown_field', 'journal', path) }
+
+      it "does not render for an unknown field" do
+        expect(subject).to be_empty
+      end
+    end
   end
 
   describe "#render_constraints_filters" do

spec/models/blacklight/solr/search_builder_spec.rb

@@ -449,6 +449,17 @@
 
       expect(solr_parameters[:fq]).to be_a_kind_of Array
     end
+
+    context "facet not defined in config" do
+      let(:single_facet) { { unknown_facet_field: "foo" } }
+      let(:user_params) { { f: single_facet } }
+
+      it "does not add facet to solr_parameters" do
+        solr_parameters = Blacklight::Solr::Request.new
+        subject.add_facet_fq_to_solr(solr_parameters)
+        expect(solr_parameters[:fq]).to be_empty
+      end
+    end
   end
 
   describe "#add_solr_fields_to_query" do