Better error message to help debug travis problem

theano/tensor/tests/test_gc.py

@@ -49,8 +49,10 @@ def test_gc_never_pickles_temporaries():
         g = theano.function([x], r, mode=theano.Mode(optimizer=optimizer,
                                                      linker=g_linker))
 
-        len_pre_f = len(pickle.dumps(f))
-        len_pre_g = len(pickle.dumps(g))
+        pre_f = pickle.dumps(f)
+        pre_g = pickle.dumps(g)
+        len_pre_f = len(pre_f)
+        len_pre_g = len(pre_g)
 
         # We can't compare the content or the length of the string
         # between f and g. 2 reason, we store some timming information
@@ -87,6 +89,9 @@ def test_gc_never_pickles_temporaries():
 
         # assert that f() didn't cause the function to grow
         # allow_gc should leave the function un-changed by calling
+        if len_pre_f != len_post_f:
+            print(pre_f)
+            print(post_f)
         assert len_pre_f == len_post_f
 
         # assert that g() didn't cause g to grow because temporaries