From b707738c2b589f212dec2d22d0578b9eeaf76cb0 Mon Sep 17 00:00:00 2001
From: ollietulloch <ollie.tulloch@nhs.net>
Date: Wed, 25 Feb 2026 09:03:39 +0000
Subject: [PATCH 1/3] Add failing test

---
 test/validators/json_schema_validator_test.rb | 25 ++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/test/validators/json_schema_validator_test.rb b/test/validators/json_schema_validator_test.rb
index 0e23d5a..b0e5da8 100644
--- a/test/validators/json_schema_validator_test.rb
+++ b/test/validators/json_schema_validator_test.rb
@@ -40,6 +40,18 @@ class JsonSchemaTestModel
       }
     }.freeze
 
+    EXTERNAL_REF_SCHEMA = {
+      '$schema' => 'https://json-schema.org/draft/2019-09/schema',
+      'type' => 'object',
+      'properties' => {
+        'name' => {
+          '$ref': 'external://structured_store/json_date_range/',
+          'type' => 'string',
+          'example' => 'John Doe'
+        }
+      }
+    }.freeze
+
     attr_accessor :draft201909_symbol_schema,
                   :hash_schema,
                   :instance_schema,
@@ -47,7 +59,8 @@ class JsonSchemaTestModel
                   :lambda_schema_dynamic,
                   :openapi31_symbol_schema,
                   :string_schema,
-                  :unexpected_class_schema
+                  :unexpected_class_schema,
+                  :external_ref_schema
 
     validates :draft201909_symbol_schema, json_schema: { allow_blank: true, schema: :draft201909 }
     validates :hash_schema, json_schema: { allow_blank: true, schema: DRAFT201909_NAME_SCHEMA }
@@ -90,6 +103,7 @@ class JsonSchemaTestModel
     validates :openapi31_symbol_schema, json_schema: { allow_blank: true, schema: :openapi31 }
     validates :string_schema, json_schema: { allow_blank: true, schema: DRAFT201909_NAME_SCHEMA.to_json }
     validates :unexpected_class_schema, json_schema: { allow_blank: true, schema: self }
+    validates :external_ref_schema, json_schema: { allow_blank: true, schema: EXTERNAL_REF_SCHEMA }
   end
 
   test 'validate test schemas' do
@@ -255,4 +269,13 @@ class JsonSchemaTestModel
       object.valid?
     end
   end
+
+  test 'allows external refs' do
+    object = JsonSchemaTestModel.new
+    object.external_ref_schema = {
+      'name' => 'John Doe'
+    }
+
+    object.valid?
+  end
 end

From 8646ce2f6a9d03047363a8a44a18213066fb8e0d Mon Sep 17 00:00:00 2001
From: ollietulloch <ollie.tulloch@nhs.net>
Date: Wed, 25 Feb 2026 09:06:45 +0000
Subject: [PATCH 2/3] add assertion

---
 test/validators/json_schema_validator_test.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/validators/json_schema_validator_test.rb b/test/validators/json_schema_validator_test.rb
index b0e5da8..ba22ba2 100644
--- a/test/validators/json_schema_validator_test.rb
+++ b/test/validators/json_schema_validator_test.rb
@@ -276,6 +276,6 @@ class JsonSchemaTestModel
       'name' => 'John Doe'
     }
 
-    object.valid?
+    assert_nothing_raised { object.valid? }
   end
 end

From d060b8de55730853efd5ac199ee2f29d22f314d2 Mon Sep 17 00:00:00 2001
From: ollietulloch <ollie.tulloch@nhs.net>
Date: Wed, 25 Feb 2026 09:08:01 +0000
Subject: [PATCH 3/3] Add default `ref_resolver`

---
 app/validators/json_schema_validator.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/validators/json_schema_validator.rb b/app/validators/json_schema_validator.rb
index c02f758..98c7028 100644
--- a/app/validators/json_schema_validator.rb
+++ b/app/validators/json_schema_validator.rb
@@ -53,7 +53,7 @@ def json_schemer(schema)
     when *NAMED_SCHEMA_VERSIONS
       JSONSchemer.send(schema)
     when String, Hash
-      JSONSchemer.schema(schema)
+      JSONSchemer.schema(schema, ref_resolver: proc { |_uri| {} })
     when JSONSchemer::Schema
       schema
     else