Per [FasterXML#106] added allowNullFields to provide the option of processing null elements of lists as empty fields or the nullCharacter during serialization instead of the default behavior which skips null elements.

Author: morbrian

src/test/java/com/fasterxml/jackson/dataformat/csv/ser/NullWritingTest.java

@@ -93,6 +93,14 @@ public void testCustomNullValueInObjectListIssue106() throws Exception
 
         String result = mapper.writer(schema).writeValueAsString(list);
         assertEquals("d0,n/a,d2\n", result);
+
+        list = Arrays.asList(null, "d1", "d2");
+        result = mapper.writer(schema).writeValueAsString(list);
+        assertEquals("n/a,d1,d2\n", result);
+
+        list = Arrays.asList("d0", "d1", null);
+        result = mapper.writer(schema).writeValueAsString(list);
+        assertEquals("d0,d1,n/a\n", result);
     }
 
     public void testDefaultNullValueInObjectListIssue106() throws Exception
@@ -104,8 +112,15 @@ public void testDefaultNullValueInObjectListIssue106() throws Exception
             .build();
 
         List list = Arrays.asList("d0", null, "d2");
-
         String result = mapper.writer(schema).writeValueAsString(list);
         assertEquals("d0,,d2\n", result);
+
+        list = Arrays.asList(null, "d1", "d2");
+        result = mapper.writer(schema).writeValueAsString(list);
+        assertEquals(",d1,d2\n", result);
+
+        list = Arrays.asList("d0", "d1", null);
+        result = mapper.writer(schema).writeValueAsString(list);
+        assertEquals("d0,d1,\n", result);
     }
 }