feat(matrix): implement querying by latest without a tag

lib/pact_broker/matrix/repository.rb

@@ -60,13 +60,20 @@ def find_all selectors
       def look_up_versions_for_tags(selectors)
         selectors.collect do | selector |
           # resource validation currently stops tag being specified without latest=true
+
           if selector[:tag] && selector[:latest]
             version = version_repository.find_by_pacticpant_name_and_latest_tag(selector[:pacticipant_name], selector[:tag])
             # validation in resource should ensure we always have a version
             {
               pacticipant_name: selector[:pacticipant_name],
               pacticipant_version_number: version.number
             }
+          elsif selector[:latest]
+            version = version_repository.find_latest_by_pacticpant_name(selector[:pacticipant_name])
+            {
+              pacticipant_name: selector[:pacticipant_name],
+              pacticipant_version_number: version.number
+            }
           else
             selector
           end

lib/pact_broker/versions/repository.rb

@@ -23,6 +23,15 @@ def find_by_pacticpant_name_and_latest_tag pacticipant_name, tag
           .first
       end
 
+      def find_latest_by_pacticpant_name pacticipant_name
+        PactBroker::Domain::Version
+          .select_all_qualified
+          .join(:pacticipants, {id: :pacticipant_id}, {implicit_qualifier: :versions})
+          .where(name_like(Sequel[:pacticipants][:name], pacticipant_name))
+          .reverse_order(:order)
+          .first
+      end
+
       def find_by_pacticipant_name_and_number pacticipant_name, number
         PactBroker::Domain::Version
           .select(Sequel[:versions][:id], Sequel[:versions][:number], Sequel[:versions][:pacticipant_id], Sequel[:versions][:order], Sequel[:versions][:created_at], Sequel[:versions][:updated_at])

spec/lib/pact_broker/matrix/repository_spec.rb

@@ -246,6 +246,52 @@ def build_selectors(hash)
             expect(subject.size).to eq 1
           end
         end
+
+        context "when the latest version is specified for a provider without a tag" do
+          before do
+            td.create_pact_with_hierarchy("A", "1.2.3", "B")
+              .create_verification(provider_version: "1.0.0")
+              .use_provider_version("1.0.0")
+              .create_verification(provider_version: "2.0.0", number: 2)
+              .use_provider_version("2.0.0")
+              .create_verification(provider_version: "3.0.0", number: 3)
+          end
+
+          let(:selectors) do
+            [
+              { pacticipant_name: "A", pacticipant_version_number: "1.2.3" },
+              { pacticipant_name: "B", latest: true }
+            ]
+          end
+
+          subject { Repository.new.find(selectors) }
+
+          it "returns the row for the version " do
+            expect(subject.first).to include provider_version_number: "3.0.0"
+            expect(subject.size).to eq 1
+          end
+        end
+
+        context "when the latest version is specified for a provider without a tag but the latest known version for a provider does not have a verification" do
+          before do
+            td.create_pact_with_hierarchy("A", "1.2.3", "B")
+              .create_verification(provider_version: "1.0.0")
+              .create_provider_version("5.0.0")
+          end
+
+          let(:selectors) do
+            [
+              { pacticipant_name: "A", pacticipant_version_number: "1.2.3" },
+              { pacticipant_name: "B", latest: true }
+            ]
+          end
+
+          subject { Repository.new.find(selectors) }
+
+          it "returns no data - this may be confusing. Might need to re-think this logic." do
+            expect(subject.size).to eq 0
+          end
+        end
       end
 
       describe "#find_for_consumer_and_provider" do