Better error message for dependentRequired

lib/openapi_first/schema/validation_error.rb

@@ -6,16 +6,16 @@ module Schema
     ValidationError = Data.define(:value, :data_pointer, :schema_pointer, :type, :details, :schema) do
       # This returns an error message for this specific error.
       # This it copied from json_schemer here to be easier to customize when passing custom data_pointers.
-      def message
+      def message # rubocop:disable Metrics/CyclomaticComplexity
         location = data_pointer.empty? ? 'root' : "`#{data_pointer}`"
 
         case type
         when 'required'
           keys = details.fetch('missing_keys', []).join(', ')
           "object at #{location} is missing required properties: #{keys}"
         when 'dependentRequired'
-          keys = details.fetch('missing_keys').join(', ')
-          "object at #{location} is missing required properties: #{keys}"
+          keys = details&.fetch('missing_keys')
+          "object at #{location} is missing required properties#{keys && " #{keys.join(', ')}"}"
         when 'string', 'boolean', 'number'
           "value at #{location} is not a #{type}"
         when 'array', 'object', 'integer'

spec/schema/validation_result_spec.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+RSpec.describe OpenapiFirst::Schema::ValidationResult do
+  def schema(hash)
+    JSONSchemer.schema(hash)
+  end
+
+  describe 'missing required field' do
+    specify do
+      validation = schema({ required: ['id'] }).validate({})
+      expect(described_class.new(validation).errors.first.message).to eq 'object at root is missing required properties: id'
+    end
+  end
+
+  describe 'missing dependentRequired field' do
+    specify do
+      validation = schema({ 'dependentRequired' => { 'id' => ['type'] } }).validate({ 'id' => '2' })
+      expect(described_class.new(validation).errors.first.message).to eq 'object at `/id` is missing required properties'
+    end
+  end
+end