Add some dubious hacks to get appropriate errors

These build on the smell of hacks from the previous commit to make this
class a bit smelly.

This adds some work arounds to get appropriate error messages for nodes
that could be one of two types. Should we need more usage of this we
probably want to refactor aspects of the ObjectFactory code to be able
to handle dual types and the TypeChecker.

lib/openapi3_parser/node_factory/schema/v3_1.rb

@@ -44,13 +44,37 @@ def boolean_input?
         end
 
         def errors
-          @errors ||= boolean_input? ? [] : super
+          # It's a bit janky that we do this method overloading here to handle
+          # the dual types of a 3.1 Schema. However this is the only node we
+          # have this dual type behaviour. We should do something more clever
+          # in the factories if there is further precedent.
+          @errors ||= if boolean_input?
+                        Validation::ErrorCollection.new
+                      elsif raw_input && !raw_input.is_a?(::Hash)
+                        error = Validation::Error.new(
+                          "Invalid type. Expected Object or Boolean",
+                          context,
+                          self.class
+                        )
+                        Validation::ErrorCollection.new([error])
+                      else
+                        super
+                      end
         end
 
         def node(node_context)
-          return super unless boolean_input?
-
-          Node::Schema::V3_1.new({ "boolean" => resolved_input }, node_context)
+          # as per #errors above, this is a bit of a nasty hack to handle
+          # dual type handling and should be refactored should there be
+          # other nodes with the same needs
+          if boolean_input?
+            Node::Schema::V3_1.new({ "boolean" => resolved_input }, node_context)
+          elsif raw_input && !raw_input.is_a?(::Hash)
+            raise Error::InvalidType,
+                  "Invalid type for #{context.location_summary}: " \
+                  "Expected Object or Boolean"
+          else
+            super
+          end
         end
 
         def build_node(data, node_context)

spec/lib/openapi3_parser/node_factory/schema/v3_1_spec.rb

@@ -50,6 +50,24 @@
 
   it_behaves_like "schema factory"
 
+  describe "type validation" do
+    it "rejects a non object or boolean input with an appropriate explanation" do
+      instance = described_class.new(create_node_factory_context(15))
+
+      expect(instance).to have_validation_error("#/").with_message("Invalid type. Expected Object or Boolean")
+    end
+
+    it "raises the appropriate error when a non object or boolean input is built" do
+      node_factory_context = create_node_factory_context("blah")
+      instance = described_class.new(node_factory_context)
+      node_context = node_factory_context_to_node_context(node_factory_context)
+
+      expect { instance.node(node_context) }
+        .to raise_error(Openapi3Parser::Error::InvalidType,
+                        "Invalid type for #/: Expected Object or Boolean")
+    end
+  end
+
   describe "boolean input" do
     it "is valid for a boolean input" do
       instance = described_class.new(create_node_factory_context(false))