diff --git a/laser_encoders/models.py b/laser_encoders/models.py
index 678efc5d..e2a81ef9 100644
--- a/laser_encoders/models.py
+++ b/laser_encoders/models.py
@@ -95,6 +95,10 @@ def __call__(self, sentences):
         if self.spm_model:
             sentences = self.tokenizer(sentences)
             return self.encode_sentences(sentences)
+        else:
+            raise ValueError(
+                "Either initialize the encoder with an spm_model or pre-tokenize and use the encode_sentences method."
+            )
 
     def _process_batch(self, batch):
         tokens = batch.tokens
diff --git a/laser_encoders/test_laser_tokenizer.py b/laser_encoders/test_laser_tokenizer.py
index cd36182d..867111cf 100644
--- a/laser_encoders/test_laser_tokenizer.py
+++ b/laser_encoders/test_laser_tokenizer.py
@@ -173,5 +173,5 @@ def test_sentence_encoder(
     sentence_embedding = sentence_encoder.encode_sentences([tokenized_text])
 
     assert isinstance(sentence_embedding, np.ndarray)
-    # assert sentence_embedding.shape == (1, 1024)
+    assert sentence_embedding.shape == (1, 1024)
     assert np.allclose(expected_array, sentence_embedding[:, :10], atol=1e-3)