Merge pull request #1221 from poldracklab/chrisfilo-patch-1

ENH: More specific errors for missing echo times

Author: effigies

fmriprep/interfaces/fmap.py

@@ -518,8 +518,15 @@ def _delta_te(in_values, te1=None, te2=None):
         if isinstance(te2, list):
             te2 = te2[1]
 
-    if te1 is None or te2 is None:
+    # For convienience if both are missing we should give one error about them
+    if te1 is None and te2 is None:
+        raise RuntimeError('EchoTime1 and EchoTime2 metadata fields not found. '
+                           'Please consult the BIDS specification.')
+    if te1 is None:
         raise RuntimeError(
-            'No echo time information found')
+            'EchoTime1 metadata field not found. Please consult the BIDS specification.')
+    if te2 is None:
+        raise RuntimeError(
+            'EchoTime2 metadata field not found. Please consult the BIDS specification.')
 
     return abs(float(te2) - float(te1))