Make it possible to define linked Data Streams using successor and predecessor

categories. This is usually needed for Wendelin applications where for some
reasons data is stored in different Data Streams which must form a logical and sorted "link".
Add test.

bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataStream.py

@@ -67,4 +67,27 @@ class DataStream(BigFile):
     for chunk in data.iterate(start_offset, end_offset - start_offset):
       chunk_list.append(chunk)
 
-    return chunk_list
\ No newline at end of file
+    return chunk_list
+
+  def getRecursiveSuccessorValueList(self):
+    """
+      Return list of all successors (Data Streams) for a Data Stream.
+    """
+    successor_list = []
+    successor = self.getSuccessorValue()
+    while successor is not None:
+      successor_list.append(successor)
+      successor = successor.getSuccessorValue()
+    return successor_list
+
+  def getRecursivePredecessorValueList(self):
+    """
+      Return list of all predecessor (Data Streams) for a Data Stream.
+    """
+    predecessor_list = []
+    predecessor = self.getPredecessorValue()
+    while predecessor is not None:
+      predecessor_list.append(predecessor)
+      predecessor = predecessor.getPredecessorValue()
+    return predecessor_list
+  
\ No newline at end of file

bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.DataStream.xml

@@ -45,9 +45,7 @@
         <item>
             <key> <string>text_content_warning_message</string> </key>
             <value>
-              <tuple>
-                <string>W: 71,  2: Arguments number differs from overridden \'appendData\' method (arguments-differ)</string>
-              </tuple>
+              <tuple/>
             </value>
         </item>
         <item>

bt5/erp5_wendelin/PortalTypeBaseCategoryTemplateItem/base_category_list.xml

@@ -50,6 +50,10 @@
  <portal_type id="Data Set Module">
   <item>business_application</item>
  </portal_type>
+ <portal_type id="Data Stream">
+  <item>predecessor</item>
+  <item>successor</item>
+ </portal_type>
  <portal_type id="Data Stream Module">
   <item>business_application</item>
  </portal_type>

bt5/erp5_wendelin/TestTemplateItem/portal_components/test.erp5.testWendelin.py

@@ -281,3 +281,43 @@ class Test(ERP5TypeTestCase):
            getattr(self.portal.portal_ingestion_policies, "default_http_json", None))
     self.assertNotEqual(None, 
            getattr(self.portal.data_supply_module, "default_http_json", None))
+
+  def test_07_LinkedDataStreamList(self):
+    """
+      Test linked Data Streams
+    """
+    data_stream_1 = self.portal.data_stream_module.newContent(title = "Data Stream 1")
+    data_stream_2 = self.portal.data_stream_module.newContent(title = "Data Stream 2")
+    data_stream_3 = self.portal.data_stream_module.newContent(title = "Data Stream 3")
+    data_stream_4 = self.portal.data_stream_module.newContent(title = "Data Stream 4")
+    data_stream_5 = self.portal.data_stream_module.newContent(title = "Data Stream 5")
+
+    # test nothing linked
+    self.assertSameSet([], data_stream_2.getRecursiveSuccessorValueList())
+    self.assertSameSet([], data_stream_2.getRecursivePredecessorValueList())
+
+    # set linked data streams (1 <--> 2 <--> 3 <--> 4 <--> 5)
+    data_stream_1.setSuccessorValue(data_stream_2)
+    data_stream_2.setSuccessorValue(data_stream_3)
+    data_stream_3.setSuccessorValue(data_stream_4)
+    data_stream_4.setSuccessorValue(data_stream_5)
+    
+    # set predecessor
+    data_stream_2.setPredecessorValue(data_stream_1)
+    data_stream_3.setPredecessorValue(data_stream_2)
+    data_stream_4.setPredecessorValue(data_stream_3)
+    data_stream_5.setPredecessorValue(data_stream_4)
+
+    # test successor
+    self.assertSameSet(data_stream_2.getRecursiveSuccessorValueList(), \
+                       [data_stream_3, data_stream_4, data_stream_5])
+    self.assertSameSet(data_stream_5.getRecursiveSuccessorValueList(), \
+                       [])
+    
+    # test predecessor
+    self.assertSameSet(data_stream_1.getRecursivePredecessorValueList(), \
+                       [])
+    self.assertSameSet(data_stream_2.getRecursivePredecessorValueList(), \
+                       [data_stream_1])
+    self.assertSameSet(data_stream_5.getRecursivePredecessorValueList(), \
+                       [data_stream_4, data_stream_3, data_stream_2, data_stream_1])
\ No newline at end of file

bt5/erp5_wendelin/bt/template_portal_type_base_category_list

@@ -18,6 +18,8 @@ Data Product Module | business_application
 Data Release Module | business_application
 Data Set Module | business_application
 Data Stream Module | business_application
+Data Stream | predecessor
+Data Stream | successor
 Data Supply Module | business_application
 Data Transformation Module | business_application
 Device Configuration Module | business_application