diff --git a/test/test_lm_finetuning.py b/test/test_lm_finetuning.py
index 6052c7cd6..b0d3684c9 100644
--- a/test/test_lm_finetuning.py
+++ b/test/test_lm_finetuning.py
@@ -36,7 +36,7 @@ def test_lm_finetuning(caplog):
         max_seq_len=12,
         next_sent_pred=True
     )
-    data_silo = DataSilo(processor=processor, batch_size=batch_size)
+    data_silo = DataSilo(processor=processor, batch_size=batch_size, max_processes=1)
 
     language_model = LanguageModel.load(lang_model)
     lm_prediction_head = BertLMHead.load(lang_model)
@@ -113,7 +113,7 @@ def test_lm_finetuning_no_next_sentence(caplog):
         max_seq_len=12,
         next_sent_pred=False
     )
-    data_silo = DataSilo(processor=processor, batch_size=batch_size)
+    data_silo = DataSilo(processor=processor, batch_size=batch_size, max_processes=1)
 
     language_model = LanguageModel.load(lang_model)
     lm_prediction_head = BertLMHead.load(lang_model)
@@ -190,7 +190,7 @@ def test_lm_finetuning_custom_vocab(caplog):
         max_seq_len=12,
         next_sent_pred=True
     )
-    data_silo = DataSilo(processor=processor, batch_size=batch_size)
+    data_silo = DataSilo(processor=processor, batch_size=batch_size, max_processes=1)
 
     language_model = LanguageModel.load(lang_model, n_added_tokens=len(tokenizer.added_tokens_decoder))
     lm_prediction_head = BertLMHead.load(lang_model, n_added_tokens=len(tokenizer.added_tokens_decoder))