Fix message and some specs

Author: Knerio

app/services/namespaces/projects/flows/create_service.rb

@@ -115,7 +115,7 @@ def create_node_function(node_function, t)
 
             if reference_value.nil?
               t.rollback_and_return! ServiceResponse.error(
-                message: 'Invalid reference value node id',
+                message: 'Referenced node function not found',
                 payload: :referenced_value_not_found
               )
             end

app/services/namespaces/projects/flows/validation/node_function/reference_value_validation_service.rb

@@ -22,7 +22,7 @@ def execute
               errors = []
 
               unless reference_value.valid?
-                errors += ValidationResult.error(:reference_value_invalid, reference_value.errors)
+                errors << ValidationResult.error(:reference_value_invalid, reference_value.errors)
               end
 
               # https://github.com/code0-tech/sagittarius/issues/508 Validate the usage and datatypes

spec/services/namespaces/projects/flows/validation/node_function/reference_value_validation_service_spec.rb

@@ -44,13 +44,10 @@
   let(:data_type_identifier) do
     create(:data_type_identifier, data_type: create(:data_type, runtime: runtime), runtime: runtime)
   end
-  let(:primary_level) { 0 }
-  let(:secondary_level) { 0 }
-  let(:tertiary_level) { nil }
   let(:reference_value) do
     create(:reference_value,
            node_function: create(:node_function))
   end
 
-  it { is_expected.to be_success }
+  it { is_expected.to be_empty }
 end