Extract a search_builder for a find one search

This gives us parity with the find many search. It allows us to always go to the search_builder for queries about the request.

Author: jcoyne

lib/blacklight/solr/repository.rb

@@ -7,9 +7,7 @@ class Repository < Blacklight::AbstractRepository
     # @param [String] id document's unique key value
     # @param [Hash] params additional solr query parameters
     def find id, params = {}
-      doc_params = params.reverse_merge(blacklight_config.default_document_solr_params)
-                         .reverse_merge(qt: blacklight_config.document_solr_request_handler)
-                         .merge(blacklight_config.document_unique_id_param => id)
+      doc_params = SingleDocSearchBuilder.new(self, id, params)
 
       solr_response = send_and_receive blacklight_config.document_solr_path || blacklight_config.solr_path, doc_params
       raise Blacklight::Exceptions::RecordNotFound if solr_response.documents.empty?
@@ -25,7 +23,7 @@ def find_many(params)
 
     ##
     # Execute a search query against solr
-    # @param [Hash] params solr query parameters
+    # @param [Hash,Blacklight::SearchBuilder] params solr query parameters
     # @param [String] path solr request handler path
     def search pos_params = nil, path: nil, params: nil, **kwargs
       if pos_params

lib/blacklight/solr/single_doc_search_builder.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module Blacklight::Solr
+  class SingleDocSearchBuilder < SearchBuilder
+    self.default_processor_chain = [:add_defaults, :add_qt, :add_unique_id]
+
+    def initialize(scope, id, other_params)
+      @other_params = other_params
+      @id = id
+      super(scope)
+    end
+
+    def add_defaults(request)
+      request.reverse_merge!(blacklight_config.default_document_solr_params).reverse_merge!(@other_params)
+    end
+
+    def add_qt(request)
+      request[:qt] ||= blacklight_config.document_solr_request_handler if blacklight_config.document_solr_request_handler
+    end
+
+    def add_unique_id(request)
+      request[blacklight_config.document_unique_id_param] = @id
+    end
+  end
+end

spec/models/blacklight/solr/repository_spec.rb

@@ -52,14 +52,14 @@
 
       it "uses the provided :qt param" do
         blacklight_config.document_solr_request_handler = 'xyz'
-        allow(subject.connection).to receive(:send_and_receive).with('select', hash_including(params: { id: '123', qt: 'abc' })).and_return(mock_response)
+        allow(subject.connection).to receive(:send_and_receive).with('select', hash_including(params: { 'id' => '123', 'qt' => 'abc' })).and_return(mock_response)
         expect(subject.find("123", qt: 'abc')).to be_a Blacklight::Solr::Response
       end
 
       it "uses the :qt parameter from the default_document_solr_params" do
         blacklight_config.default_document_solr_params[:qt] = 'abc'
         blacklight_config.document_solr_request_handler = 'xyz'
-        allow(subject.connection).to receive(:send_and_receive).with('select', hash_including(params: { id: '123', qt: 'abc' })).and_return(mock_response)
+        allow(subject.connection).to receive(:send_and_receive).with('select', hash_including(params: { 'id' => '123', 'qt' => 'abc' })).and_return(mock_response)
         expect(subject.find("123")).to be_a Blacklight::Solr::Response
       end
     end