core: fix TextDocument.getData with empty text content

bt5/erp5_web/TestTemplateItem/portal_components/test.erp5.testERP5Web.py

@@ -252,6 +252,7 @@ class TestERP5Web(ERP5TypeTestCase):
     page.edit(text_content='<b>OK</b>')
     self.assertEqual('text/html', page.getContentType())
     self.assertEqual('<b>OK</b>', page.getTextContent())
+    self.assertEqual(b'<b>OK</b>', page.getData())
 
   def test_WebPageAsTextUTF8(self):
     """Check if Web Page's asText() returns utf-8 string correctly
@@ -270,6 +271,16 @@ class TestERP5Web(ERP5TypeTestCase):
     self.tic()
     self.assertEqual('Hé!', page.asText().strip())
 
+  def test_WebPageAsTextEmpty(self):
+    page = self.web_page_module.newContent(portal_type='Web Page')
+    self.tic()
+    self.assertIsNone(page.getTextContent())
+    self.assertIsNone(page.getData())
+    default = []
+    self.assertIs(page.getData(default), default)
+    self.assertEqual(page.asText(), '')
+    self.assertEqual(page.getSearchableText(), '')
+
   def test_WebPageAsTextWrap(self):
     """Check if Web Page's asText() is wrapped by certain column width.
     """

product/ERP5/bootstrap/erp5_core/DocumentTemplateItem/portal_components/document.erp5.TextDocument.py

@@ -417,7 +417,7 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin, TextContent
     return self._setContentType(value)
 
   def getData(self, default=_MARKER):
-    # type: () -> bytes | PData
+    # type: (bytes) -> bytes | PData
     """getData must returns original content but TextDocument accepts
     data or text_content to store original content.
     Fallback on text_content property if data is not defined
@@ -427,7 +427,9 @@ class TextDocument(CachedConvertableMixin, BaseConvertableFileMixin, TextContent
         data = self._baseGetTextContent()
       else:
         data = self._baseGetTextContent(default)
-      return str2bytes(data)
+        if data is default:
+          return default
+      return str2bytes(data) if data is not None else None
     else:
       if default is _MARKER:
         return File.getData(self)