test(derive): close seventh mutation shard

Prove all state, async, and Result registration combinations and the exact no-generated-component repair diagnostic.

req: component/003

req: derive_handler/003

req: test/020

req: test/021

req: test/022

req: test/023

hemx-derive/src/lib.rs

@@ -1016,13 +1016,14 @@ fn compile_error(message: &str) -> TokenStream {
 mod tests {
     use super::{
         add_app_registry_helper, add_component_register_helper, client_handler_has_inputs,
-        component_handler_names, expand_handler_function, form_contract_errors, form_decode_fields,
-        form_fields, form_impl_generics, form_model_type, form_resource_id, generic_inner_type,
-        handle_params, handle_requires_form, handler_arg_names, handler_form_model_type,
-        handler_placement, handler_syms_path, has_form_param, has_non_unit_return, is_type_named,
+        component_contract_errors, component_handler_names, component_registration_call,
+        expand_handler_function, form_contract_errors, form_decode_fields, form_fields,
+        form_impl_generics, form_model_type, form_resource_id, generic_inner_type, handle_params,
+        handle_requires_form, handler_arg_names, handler_form_model_type, handler_placement,
+        handler_syms_path, has_form_param, has_non_unit_return, is_type_named,
         join_contract_errors, missing_component_handlers, missing_form_generated_files_message,
         missing_handle_params, missing_handler_generated_files_message, parser_type,
-        returns_result, rust_ident, syms_contains_handle, HandlerPlacement,
+        returns_result, rust_ident, syms_contains_handle, ComponentHandler, HandlerPlacement,
     };
     use quote::{quote, ToTokens};
     use syn::{parse_quote, ItemFn, Type};
@@ -1469,6 +1470,55 @@ mod tests {
         let _ = std::fs::remove_file(path);
     }
 
+    #[test]
+    fn component_registration_selects_each_state_async_result_shape() {
+        let component_ident: syn::Ident = parse_quote!(todos);
+        let expected = [
+            (0, false, false, quote!(.on(super::todos::save, save))),
+            (0, false, true, quote!(.on_result(super::todos::save, save))),
+            (0, true, false, quote!(.on_async(super::todos::save, save))),
+            (
+                0,
+                true,
+                true,
+                quote!(.on_async_result(super::todos::save, save)),
+            ),
+            (1, false, false, quote!(.on_state(super::todos::save, save))),
+            (
+                1,
+                false,
+                true,
+                quote!(.on_state_result(super::todos::save, save)),
+            ),
+            (
+                1,
+                true,
+                false,
+                quote!(.on_state_async(super::todos::save, save)),
+            ),
+            (
+                1,
+                true,
+                true,
+                quote!(.on_state_async_result(super::todos::save, save)),
+            ),
+        ];
+        for (typed_arg_count, is_async, returns_result, expected) in expected {
+            let handler = ComponentHandler {
+                ident: parse_quote!(save),
+                is_async,
+                returns_result,
+                typed_arg_count,
+            };
+            assert_eq!(
+                component_registration_call(&handler, &component_ident).to_string(),
+                expected.to_string(),
+                "args={typed_arg_count} async={is_async} result={returns_result}"
+            );
+        }
+        // test req: component/003 req: derive_handler/003
+    }
+
     #[test]
     fn component_handlers_match_generated_handles() {
         let path = std::env::temp_dir().join("hemx-derive-component-test.syms");
@@ -1495,7 +1545,14 @@ mod tests {
             vec!["delete"]
         );
 
-        let _ = std::fs::remove_file(path);
+        let _ = std::fs::remove_file(&path);
+        assert_eq!(
+            component_contract_errors(&path, Some("missing"), &items),
+            vec![
+                "#[hemx::component(\"missing\")] does not match any generated handles; no generated components with handles are available; add a data-hemx-handle to the component template or check build.rs generation",
+                "#[hemx::component] handler(s) not declared by this component's generated handles: create; move them to the matching component module or add data-hemx-handle in .heml",
+            ]
+        );
     }
 
     #[test]