A-done

lib/tabasco.rb

@@ -9,6 +9,9 @@
 module Tabasco
   class Error < StandardError; end
   class PreconditionNotMetError < Error; end
+  class InconsistentPortalKlassError < Error; end
+  class PortalNotConfiguredError < Error; end
+  class PortalAlreadyConfiguredError < Error; end
 
   def self.configure
     yield configuration.dsl

lib/tabasco/configuration.rb

@@ -2,9 +2,6 @@
 
 module Tabasco
   class Configuration
-    class Error < ::Tabasco::Error; end
-    class PortalNotConfigured < Error; end
-
     def initialize
       @portals = {}
     end
@@ -23,7 +20,7 @@ def portal(name)
         portals. Refer to the README document for more information.
       ERR
 
-      raise PortalNotConfigured, message
+      raise PortalNotConfiguredError, message
     end
 
     class DSL
@@ -54,7 +51,10 @@ def portal(portal_name, klass = nil, test_id: nil)
 
         portals = configuration.instance_variable_get(:@portals)
 
-        raise Error, "The portal #{portal_name.inspect} is already defined" if portals.key?(portal_name.to_sym)
+        if portals.key?(portal_name.to_sym)
+          raise PortalAlreadyConfiguredError,
+            "The portal #{portal_name.inspect} is already defined"
+        end
 
         portals[portal_name] = {klass:, test_id:}
 

lib/tabasco/section.rb

@@ -35,9 +35,16 @@ def section(name, klass = nil, test_id: nil, &)
         define_inline_section(name, klass, test_id: test_id, &)
       end
 
-      def portal(name, local_concrete_klass = nil, &)
+      def portal(name, concrete_klass = nil, local_concrete_klass = nil, &)
         Tabasco.configuration.portal(name) in { klass:, test_id: }
 
+        if klass && concrete_klass && !concrete_klass.ancestors.include?(klass)
+          raise InconsistentPortalKlassError,
+            "The class #{concrete_klass} provided to the portal \"#{name}\" " \
+            "must inherit from the configured portal class #{klass}."
+        end
+
+        klass = concrete_klass || klass
         define_inline_section(name, klass, test_id:, portal: true, &)
       end
 

spec/tabasco/configuration_spec.rb

@@ -43,15 +43,15 @@
     it "raises an error when trying to read a portal that has not been defined" do
       expect do
         configuration.portal(:my_portal)
-      end.to raise_error(Tabasco::Configuration::PortalNotConfigured)
+      end.to raise_error(Tabasco::PortalNotConfiguredError)
     end
 
     it "raises an error when trying to define a portal with the same name twice" do
       dsl.portal(:my_portal)
 
       expect do
         dsl.portal(:my_portal)
-      end.to raise_error(Tabasco::Configuration::Error, "The portal :my_portal is already defined")
+      end.to raise_error(Tabasco::PortalAlreadyConfiguredError, "The portal :my_portal is already defined")
     end
   end
 end

spec/tabasco/section_spec.rb

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
 RSpec.describe Tabasco::Section do
-  def def_klass(container_test_id: :section_container, &block)
-    Class.new(described_class) do
+  def def_klass(parent: described_class, container_test_id: :section_container, &block)
+    Class.new(parent) do
       container_test_id container_test_id
 
       ensure_loaded { true }
@@ -199,7 +199,7 @@ def has_custom_query?
     end
 
     it "raises an error if the portal has not been configured" do
-      expect { section_klass.load.ipsum.lorem }.to raise_error(Tabasco::Configuration::PortalNotConfigured)
+      expect { section_klass.load.ipsum.lorem }.to raise_error(Tabasco::PortalNotConfiguredError)
     end
 
     context "when the portal is configured" do
@@ -289,6 +289,34 @@ def hello
 
         expect(section.portal).not_to be(section.another_portal)
       end
+
+      it "can be assigned a different concrete class as long as it's a subclass of the configured one" do
+        another_concrete_klass = def_klass(parent: concrete_klass, container_test_id: nil) do
+          def hello
+            "Hello from the multiverse!"
+          end
+        end
+
+        section_klass = def_klass do
+          portal :portal, another_concrete_klass
+        end
+
+        expect(section_klass.load.portal.hello).to eq("Hello from the multiverse!")
+      end
+
+      it "raises an error if the provided concrete class is not a subclass of the configured one" do
+        another_concrete_klass = def_klass(container_test_id: nil) do
+          def hello
+            "Hello from the multiverse!"
+          end
+        end
+
+        expect do
+          def_klass do
+            portal :portal, another_concrete_klass
+          end
+        end.to raise_error(Tabasco::InconsistentPortalKlassError)
+      end
     end
   end
 end