fixed bug whereby null values for list-valued column were not properl…

…y read from the sqlite db

CHANGES

@@ -1,6 +1,13 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+- Fixed handling of null values for list-valued columns when reading from sqlite db.
+
+
+
 Version 3.2.2
 -------------
 

setup.cfg

@@ -106,6 +106,7 @@ source =
 
 [coverage:report]
 show_missing = true
+skip_covered = true
 
 [tox:tox]
 envlist = py38, py39, py310, py311, py312

src/csvw/db.py

@@ -427,7 +427,9 @@ def read(self) -> typing.Dict[str, typing.List[typing.OrderedDict]]:
                     d = collections.OrderedDict()
                     for k, v in zip(cols, row):
                         if k in seps:
-                            if not v:
+                            if v is None:
+                                d[k] = None
+                            elif not v:
                                 d[k] = []
                             elif seps[k] == 'json':
                                 d[k] = json.loads(v)

tests/test_db.py

@@ -68,9 +68,10 @@ def test_list_valued_non_text(tg, translate):
     tg.tables[0].tableSchema.columns.append(Column.fromvalue(
         {'separator': '#', 'name': 'v', 'datatype': 'integer'}))
     db = Database(tg, translate=translate)
-    db.write(data=[{'v': [1, 2, 3]}])
+    db.write(data=[{'v': [1, 2, 3]}, {'v': None}])
     data = db.read()['data']
     assert data[0]['vv'] == [1, 2, 3]
+    assert data[1]['vv'] is None
 
 
 def test_required(tg):