chore: import upstream snapshot with attribution

tests/js/components/checkbox-handler.test.js

@@ -0,0 +1,130 @@
+/**
+ * Tests for components/checkbox_handler.js
+ *
+ * Tests the checkbox-hidden input fallback pattern that ensures
+ * both checked and unchecked states are submitted in HTML forms.
+ */
+
+let handler;
+
+beforeAll(async () => {
+    await import('@js/components/checkbox_handler.js');
+    handler = window.checkboxHandler;
+});
+
+describe('CheckboxHandler', () => {
+    let form;
+
+    beforeEach(() => {
+        form = document.createElement('form');
+        document.body.appendChild(form);
+    });
+
+    afterEach(() => {
+        form.remove();
+    });
+
+    describe('setupCheckbox', () => {
+        it('disables hidden input when checkbox is checked', () => {
+            const checkbox = document.createElement('input');
+            checkbox.type = 'checkbox';
+            checkbox.checked = true;
+            checkbox.setAttribute('data-hidden-fallback', 'hidden-1');
+
+            const hidden = document.createElement('input');
+            hidden.type = 'hidden';
+            hidden.id = 'hidden-1';
+            hidden.value = 'false';
+
+            form.appendChild(checkbox);
+            form.appendChild(hidden);
+
+            handler.setupCheckbox(checkbox);
+            expect(hidden.disabled).toBe(true);
+        });
+
+        it('enables hidden input when checkbox is unchecked', () => {
+            const checkbox = document.createElement('input');
+            checkbox.type = 'checkbox';
+            checkbox.checked = false;
+            checkbox.setAttribute('data-hidden-fallback', 'hidden-2');
+
+            const hidden = document.createElement('input');
+            hidden.type = 'hidden';
+            hidden.id = 'hidden-2';
+            hidden.value = 'false';
+
+            form.appendChild(checkbox);
+            form.appendChild(hidden);
+
+            handler.setupCheckbox(checkbox);
+            expect(hidden.disabled).toBe(false);
+        });
+
+        it('toggles hidden input on change event', () => {
+            const checkbox = document.createElement('input');
+            checkbox.type = 'checkbox';
+            checkbox.checked = false;
+            checkbox.setAttribute('data-hidden-fallback', 'hidden-3');
+
+            const hidden = document.createElement('input');
+            hidden.type = 'hidden';
+            hidden.id = 'hidden-3';
+
+            form.appendChild(checkbox);
+            form.appendChild(hidden);
+
+            handler.setupCheckbox(checkbox);
+            expect(hidden.disabled).toBe(false);
+
+            checkbox.checked = true;
+            checkbox.dispatchEvent(new Event('change'));
+            expect(hidden.disabled).toBe(true);
+
+            checkbox.checked = false;
+            checkbox.dispatchEvent(new Event('change'));
+            expect(hidden.disabled).toBe(false);
+        });
+    });
+
+    describe('cleanup', () => {
+        it('removes event listener from checkbox', () => {
+            const checkbox = document.createElement('input');
+            checkbox.type = 'checkbox';
+            checkbox.setAttribute('data-hidden-fallback', 'hidden-4');
+
+            const hidden = document.createElement('input');
+            hidden.type = 'hidden';
+            hidden.id = 'hidden-4';
+
+            form.appendChild(checkbox);
+            form.appendChild(hidden);
+
+            handler.setupCheckbox(checkbox);
+            expect(checkbox._checkboxHandlerCleanup).toBeTypeOf('function');
+
+            handler.cleanup(checkbox);
+            expect(checkbox._checkboxHandlerCleanup).toBeUndefined();
+        });
+    });
+
+    describe('prepareFormSubmission', () => {
+        it('syncs all checkbox-hidden pairs before submit', () => {
+            const checkbox = document.createElement('input');
+            checkbox.type = 'checkbox';
+            checkbox.checked = true;
+            checkbox.setAttribute('data-hidden-fallback', 'hidden-5');
+
+            const hidden = document.createElement('input');
+            hidden.type = 'hidden';
+            hidden.id = 'hidden-5';
+            hidden.disabled = false;
+
+            form.appendChild(checkbox);
+            form.appendChild(hidden);
+
+            handler.prepareFormSubmission(form);
+            expect(hidden.disabled).toBe(true);
+        });
+    });
+});