Update testb.py

testb.py

@@ -37,7 +37,7 @@ class TestB(datasets.GeneratorBasedBuilder):
             datasets.SplitGenerator(
                 name=datasets.Split.TRAIN,
                 gen_kwargs={
-                    "data_file": os.path.join(dl_dir "test.json"),
+                    "data_file": os.path.join(dl_dir, "test.json"),
                     "split": datasets.Split.TRAIN,
                 },
             )