ERP5: fix content_type property

content_type is a bit special, because CMF's PortalFolderBase also have
a content_type method, so this was confusing ERP5Type dynamic properties
system. When the property was never set, the default value was the
method acquired from PortalFolderBase.

Fixes this by defining conten_type class attribute where needed.

This also fixes an old expected failure test, it's now possible to use
edit(content_type=something) in document without content type property
set. It works now, but thanks to what seems to be outdated code in
_valid_property_id from product/ERP5Type/patches/PropertyManager.py,
because we have stopped setting all properties to None in Base years
ago. For now, this works, but because of an outdated condition in
_valid_property_id. We may revisit later in the future.

product/ERP5/Document/File.py

@@ -74,7 +74,6 @@ class File(Document, CMFFile):
   security.declareObjectProtected(Permissions.AccessContentsInformation)
 
   # Default global values
-  content_type = '' # Required for WebDAV support (default value)
   data = '' # A hack required to use OFS.Image.index_html without calling OFS.Image.__init__
 
   # Default Properties

product/ERP5/tests/testERP5Base.py

@@ -1379,10 +1379,7 @@ class TestERP5Base(ERP5TypeTestCase):
     self.assertEqual('organisation@example.com',
       organisation.getAlternateEmailCoordinateText())
 
-  # Marked as expectedFailure as it shall be never possible to use edit method to set
-  # local property which would override existing method
-  @expectedFailure
-  def test_content_type_property(self):
+  def test_content_type_local_property(self):
     portal_type = 'Person'
     person_module = self.portal.getDefaultModule(portal_type)
     person = person_module.newContent(portal_type=portal_type)
@@ -1393,6 +1390,20 @@ class TestERP5Base(ERP5TypeTestCase):
     # edit content_type on document which has no content_type property configured
     person.edit(content_type='text/xml')
 
+  def test_EmbeddedFile_content_type(self):
+    embedded_file = self.portal.person_module.newContent(
+        portal_type='Person'
+    ).newContent(
+        portal_type='Embedded File'
+    )
+
+    self.assertFalse(embedded_file.hasContentType())
+    self.assertEqual('text/plain', embedded_file.getContentType('text/plain'))
+
+    embedded_file.edit(content_type='text/xml')
+    self.assertEqual('text/xml', embedded_file.getContentType())
+    self.assertEqual('text/xml', embedded_file.getProperty('content_type'))
+
   def test_BankAccount_validateIBAN(self):
     self.assertTrue(
         self.portal.BankAccount_validateIBAN(

product/ERP5Form/Form.py

@@ -637,6 +637,12 @@ class ERP5Form(Base, ZMIForm, ZopePageTemplate):
     objectItems = ZMIForm.objectItems
     objectValues = ZMIForm.objectValues
 
+    # If content_type is not text/html ZopePageTemplate will check that the
+    # source is well formed XML, but this does not really applies to Forms,
+    # they don't have source. By setting content_type here we make sure we
+    # don't get ERP5Type's Base default content_type.
+    content_type = ZopePageTemplate.content_type
+
     def __init__(self, id, title, unicode_mode=0, encoding='UTF-8',
                  stored_encoding='UTF-8'):
         """Initialize form.

product/ERP5Type/Base.py

@@ -847,6 +847,8 @@ class Base( CopyContainer,
   security.declareProtected( Permissions.AccessContentsInformation, 'getId' )
   getId = BaseAccessor.Getter('getId', 'id', 'string')
 
+  content_type = None # content_type is a property in ERP5, but a method in CMF
+
   # Debug
   security.declareProtected(Permissions.AccessContentsInformation,
                             'getOid')

product/ERP5Type/Core/Folder.py

@@ -707,6 +707,7 @@ class Folder(OFSFolder2, CMFBTreeFolder, CMFHBTreeFolder, Base, FolderMixIn):
   PUT_factory = None
   # XXX Prevent inheritance from PortalFolderBase
   description = None
+  content_type = None # content_type is a property in ERP5, but a method in CMF
 
   # Per default we use BTree folder
   _folder_handler = BTREE_HANDLER