suggestion of a fix

Author: miltoncamachocamacho

sdcflows/tests/test_fieldmaps.py

@@ -120,8 +120,8 @@ def test_FieldmapEstimation(dsA_dir, inputfiles, method, nsources):
         fm.FieldmapEstimation(sources, bids_id=fe.bids_id)
 
     # Ensure we can't instantiate one more estimation with same sources
-    with pytest.raises(ValueError):
-        fm.FieldmapEstimation(sources, bids_id=f'my{fe.bids_id}')
+    with pytest.warns(UserWarning, match=r"is already .* in mapping"):
+        fm.FieldmapEstimation(sources, bids_id=f"my{fe.bids_id}")
 
     # Exercise workflow creation
     wf = fe.get_workflow()

sdcflows/utils/bimap.py

@@ -23,6 +23,7 @@
 """A bidirectional hashmap."""
 
 import re
+import warnings
 
 _autokey_pat = re.compile(r'^auto_(\d+)$')
 
@@ -144,9 +145,7 @@ def __setitem__(self, key, value):
         if self.__contains__(key):
             raise KeyError(f"'{key}' is already {'a value' * (key in self._inverse)} in mapping")
         if self.__contains__(value):
-            raise ValueError(
-                f"'{value}' is already {'a key' * (value not in self._inverse)} in mapping"
-            )
+            warnings.warn( f"'{value}' is already {'a key' * (value not in self._inverse)} in mapping", UserWarning )
 
         super().__setitem__(key, value)
         self._inverse[value] = key