Fix some review related code snippets

arkindex_worker/cache.py

@@ -21,6 +21,13 @@ CachedElement = namedtuple(
 )
 
 
+def convert_table_tuple(table):
+    if table == "elements":
+        return CachedElement
+    else:
+        raise NotImplementedError
+
+
 class LocalDB(object):
     def __init__(self, path):
         self.db = sqlite3.connect(path)
@@ -43,11 +50,27 @@ class LocalDB(object):
         self.db.commit()
 
     def fetch(self, table, where=[]):
+        """
+        where parameter is a list containing 3-values tuples defining an SQL WHERE condition.
+
+        e.g: where=[("id", "LIKE", "%0000%"), ("id", "NOT LIKE", "%1111%")]
+             stands for "WHERE id LIKE '%0000%' AND id NOT LIKE '%1111%'" in SQL.
+
+        This method only supports 'AND' SQL conditions.
+        """
+
         sql = f"SELECT * FROM {table}"
         if where:
+            assert isinstance(where, list), "where should be a list"
+            assert all(
+                isinstance(condition, tuple) and len(condition) == 3
+                for condition in where
+            ), "where conditions should be tuples of 3 values"
+
             sql += " WHERE "
             sql += " AND ".join(
                 [f"{field} {operator} (?)" for field, operator, _ in where]
             )
         self.cursor.execute(sql, [value for _, _, value in where])
-        return self.cursor.fetchall()
+        tuple_type = convert_table_tuple(table)
+        return [tuple_type(**dict(row)) for row in self.cursor.fetchall()]

arkindex_worker/worker.py

@@ -897,18 +897,17 @@ class ElementsWorker(BaseWorker):
             }, "When using the local cache, you can only filter by 'type' and/or 'worker_version'"
 
             conditions = [("parent_id", "=", convert_str_uuid_to_hex(element.id))]
-            conditions += [("type", "=", type)] if type else []
-            conditions += (
-                [("worker_version_id", "=", convert_str_uuid_to_hex(worker_version))]
-                if worker_version
-                else []
-            )
+            if type:
+                conditions.append(("type", "=", type))
+            if worker_version:
+                conditions.append(
+                    ("worker_version_id", "=", convert_str_uuid_to_hex(worker_version))
+                )
 
             children = self.cache.fetch(
                 "elements",
                 where=conditions,
             )
-            children = [CachedElement(**dict(child)) for child in children]
         else:
             children = self.api_client.paginate(
                 "ListElementChildren", id=element.id, **query_params

tests/test_cache.py

@@ -134,15 +134,15 @@ def test_fetch_all():
     db_path = f"{FIXTURES}/lines.sqlite"
     cache = LocalDB(db_path)
     cache.create_tables()
-    rows = cache.fetch("elements")
-    assert [CachedElement(**dict(row)) for row in rows] == ELEMENTS_TO_INSERT
+    children = cache.fetch("elements")
+    assert children == ELEMENTS_TO_INSERT
 
 
 def test_fetch_with_where():
     db_path = f"{FIXTURES}/lines.sqlite"
     cache = LocalDB(db_path)
     cache.create_tables()
-    rows = cache.fetch(
+    children = cache.fetch(
         "elements",
         where=[
             (
@@ -153,4 +153,4 @@ def test_fetch_with_where():
             ("id", "LIKE", "%1111%"),
         ],
     )
-    assert [CachedElement(**dict(row)) for row in rows] == [ELEMENTS_TO_INSERT[0]]
+    assert children == [ELEMENTS_TO_INSERT[0]]