diff --git a/pytorch_transformers/tests/tokenization_gpt2_test.py b/pytorch_transformers/tests/tokenization_gpt2_test.py
index fbeaa2a6dfc..c7e24e8364b 100644
--- a/pytorch_transformers/tests/tokenization_gpt2_test.py
+++ b/pytorch_transformers/tests/tokenization_gpt2_test.py
@@ -42,7 +42,7 @@ class GPT2TokenizationTest(CommonTestCases.CommonTokenizerTester):
         self.vocab_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['vocab_file'])
         self.merges_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['merges_file'])
         with open(self.vocab_file, "w", encoding="utf-8") as fp:
-            fp.write(json.dumps(vocab_tokens))
+            fp.write(json.dumps(vocab_tokens) + "\n")
         with open(self.merges_file, "w", encoding="utf-8") as fp:
             fp.write("\n".join(merges))
 
diff --git a/pytorch_transformers/tests/tokenization_roberta_test.py b/pytorch_transformers/tests/tokenization_roberta_test.py
index e1e7f45efd1..45e45d645ce 100644
--- a/pytorch_transformers/tests/tokenization_roberta_test.py
+++ b/pytorch_transformers/tests/tokenization_roberta_test.py
@@ -41,7 +41,7 @@ class RobertaTokenizationTest(CommonTestCases.CommonTokenizerTester):
         self.vocab_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['vocab_file'])
         self.merges_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['merges_file'])
         with open(self.vocab_file, "w", encoding="utf-8") as fp:
-            fp.write(json.dumps(vocab_tokens))
+            fp.write(json.dumps(vocab_tokens) + "\n")
         with open(self.merges_file, "w", encoding="utf-8") as fp:
             fp.write("\n".join(merges))