fix: correctly identify database version when schema_migrations table…

… is empty

lib/pact_broker/db/version.rb

@@ -3,10 +3,27 @@ module DB
     class Version
       def self.call database_connection
         if database_connection.tables.include?(:schema_migrations)
-          last_migration_filename = database_connection[:schema_migrations].order(:filename).last[:filename]
-          last_migration_filename.split("_", 2).first.to_i
+          version_from_schema_migrations(database_connection)
         elsif database_connection.tables.include?(:schema_info)
-          database_connection[:schema_info].first[:version]
+          version_from_schema_info(database_connection)
+        else
+          0
+        end
+      end
+
+      private_class_method def self.version_from_schema_migrations(database_connection)
+        last_migration = database_connection[:schema_migrations].order(:filename).last
+        if last_migration
+          last_migration[:filename].split("_", 2).first.to_i
+        else
+          0
+        end
+      end
+
+      private_class_method def self.version_from_schema_info(database_connection)
+        schema_info = database_connection[:schema_info].first
+        if schema_info
+          schema_info[:version]
         else
           0
         end