chore(form-core): make testing form registration easier

packages/form-core/package.json

@@ -20,6 +20,7 @@
     "src",
     "test",
     "test-helpers",
+    "test-suites",
     "translations",
     "types"
   ],

packages/form-core/src/registration/FormRegisteringMixin.js

@@ -42,6 +42,14 @@ const FormRegisteringMixinImplementation = superclass =>
 
     disconnectedCallback() {
       super.disconnectedCallback();
+      this.__unregisterFormElement();
+    }
+
+    /**
+     * Putting this in a separate method makes testing easier
+     * @private
+     */
+    __unregisterFormElement() {
       if (this._parentFormGroup) {
         this._parentFormGroup.removeFormElement(/** @type {* & FormRegisteringHost} */ (this));
       }

packages/form-core/types/registration/FormRegisteringMixinTypes.d.ts

@@ -14,6 +14,8 @@ export declare class FormRegisteringHost {
    * ChoiceGroup
    */
   protected _parentFormGroup: FormRegistrarHost | undefined;
+
+  private __unregisterFormElement: void;
 }
 
 export declare function FormRegisteringImplementation<T extends Constructor<LitElement>>(