Add a message to assertion errors

Closes #23 (closed)

nerval/evaluate.py

@@ -58,10 +58,10 @@ def compute_matches(
 
     Output : {TAG1 : nb_entity_matched, ...}, example : {'All': 1, 'OCC': 0, 'PER': 1}
     """
-    assert annotation
-    assert prediction
-    assert labels_annot
-    assert labels_predict
+    assert annotation, "Annotation is empty"
+    assert prediction, "Prediction is empty"
+    assert labels_annot, "Annotation labels are empty"
+    assert labels_predict, "Prediction labels are empty"
 
     entity_count = {"All": 0}
     last_tag = NOT_ENTITY_TAG
@@ -190,9 +190,9 @@ def get_labels_aligned(original: str, aligned: str, labels_original: list) -> li
     Output format :
         list of strings
     """
-    assert original
-    assert aligned
-    assert labels_original
+    assert original, "Original is empty"
+    assert aligned, "Aligned is empty"
+    assert labels_original, "Original labels are empty"
 
     labels_aligned = []
     index_original = 0