Make test fail when optimization error is raised

theano/scan_module/tests/test_scan.py

@@ -2524,12 +2524,20 @@ class T_Scan(unittest.TestCase):
         # recurrent output of a scan node instead of taking the result
         # returned by the scan() function
 
+        # Obtain a compilation mode that will cause the test to fail if an
+        # exception occurs in the optimization process
+        on_opt_error = theano.config.on_opt_error
+        theano.config.on_opt_error = "raise"
+        mode = theano.compile.get_default_mode()
+        theano.config.on_opt_error = on_opt_error
+
         x = tensor.scalar()
         seq = tensor.vector()
         outputs_info=[x, tensor.zeros_like(x)]
         (out1, out2), updates = theano.scan(lambda a, b, c : (a + b, b + c),
                                             sequences=seq,
-                                            outputs_info=outputs_info)
+                                            outputs_info=outputs_info,
+                                            mode=mode)
 
         # Obtain a reference to the scan outputs before the subtensor and
         # compile a function with them as outputs
@@ -2537,7 +2545,9 @@ class T_Scan(unittest.TestCase):
         assert isinstance(out2.owner.op, tensor.subtensor.Subtensor)
         out1_direct = out1.owner.inputs[0]
         out2_direct = out2.owner.inputs[0]
-        fct = theano.function([x, seq], [out1_direct[:-1], out2_direct[:-1]])
+        fct = theano.function([x, seq],
+                              [out1_direct[:-1], out2_direct[:-1]],
+                              mode=mode)
 
         # Test the function to ensure valid outputs
         floatX = theano.config.floatX