Expected
Referencing a component that does not meet the criteria an object requires should be considered invalid.
Example
A Response object referencing a component that does not contain a "description" should be considered invalid.

Reasoning
"description" is a REQUIRED property for a Response object.
Actual
Referencing a component that does not meet the criteria an object requires is considered valid.
Example
$api = Reader::readFromJson(<<<JSON{ "openapi": "3.0.0", "info": { "title": "Test API", "version": "1.0.0" }, "paths": { "/path": { "get": { "responses": { "200": { "\$ref": "#/components/schemas/notAResponse" } } } } }, "components": { "schemas": { "notAResponse": { "type": "integer" } } }}JSON);
var_dump($api->validate()); // bool(true)
Expected
Referencing a component that does not meet the criteria an object requires should be considered invalid.
Example
A Response object referencing a component that does not contain a "description" should be considered invalid.
Reasoning
"description" is a REQUIRED property for a Response object.
Actual
Referencing a component that does not meet the criteria an object requires is considered valid.
Example