Fix: keep signature when inserting a template #621

lib/__tests__/template-utils.test.ts

@@ -10,6 +10,7 @@ import {
   filterTemplates,
   exportTemplates,
   importTemplates,
+  spliceTemplateAboveSignature,
 } from '../template-utils';
 import type { EmailTemplate } from '../template-types';
 
@@ -333,3 +334,39 @@ describe('filterTemplates', () => {
     expect(filterTemplates(templates, 'xyz')).toHaveLength(0);
   });
 });
+
+describe('spliceTemplateAboveSignature', () => {
+  const template = '<p>Template body</p>';
+
+  it('keeps the signature block below the template (separator marker)', () => {
+    const prev = '<p></p><p data-signature-block="separator">-- </p><div>My signature</div><p data-signature-block="end"></p>';
+    expect(spliceTemplateAboveSignature(prev, template)).toBe(
+      '<p>Template body</p><p data-signature-block="separator">-- </p><div>My signature</div><p data-signature-block="end"></p>'
+    );
+  });
+
+  it('keeps the signature block below the template (start marker, no separator)', () => {
+    const prev = '<p>old draft text</p><p data-signature-block="start"></p><div>My signature</div><p data-signature-block="end"></p>';
+    expect(spliceTemplateAboveSignature(prev, template)).toBe(
+      '<p>Template body</p><p data-signature-block="start"></p><div>My signature</div><p data-signature-block="end"></p>'
+    );
+  });
+
+  it('replaces the whole body when there is no signature block', () => {
+    expect(spliceTemplateAboveSignature('<p>old draft text</p>', template)).toBe(template);
+  });
+
+  it('keeps everything from the start marker onward when the end marker is missing', () => {
+    const prev = '<p>old</p><p data-signature-block="separator">-- </p><div>My signature</div>';
+    expect(spliceTemplateAboveSignature(prev, template)).toBe(
+      '<p>Template body</p><p data-signature-block="separator">-- </p><div>My signature</div>'
+    );
+  });
+
+  it('discards user edits above the signature', () => {
+    const prev = '<p>half-written draft</p><p data-signature-block="separator">-- </p><div>Sig</div><p data-signature-block="end"></p>';
+    const result = spliceTemplateAboveSignature(prev, template);
+    expect(result).not.toContain('half-written draft');
+    expect(result).toContain('Sig');
+  });
+});