diff --git a/tests/test_TFNetworkRecLayer.py b/tests/test_TFNetworkRecLayer.py
index e949bc6c9..0489db566 100644
--- a/tests/test_TFNetworkRecLayer.py
+++ b/tests/test_TFNetworkRecLayer.py
@@ -2104,7 +2104,8 @@ def test_target_with_beam():
       }
     }, "target": teacher_target, "max_seq_len": "max_len_from('base:teacher_encoder') * 3", "trainable": False},
 
-    # the teacher's decision layer is actually not used, since the hypotheses data is fetched from the teacher's choice layer (or teacher_output)...
+    # the teacher's decision layer is actually not used,
+    # since the hypotheses data is fetched from the teacher's choice layer (or teacher_output)...
     "teacher_decision": {
       "class": "decide", "from": ["teacher_output"], "loss": "edit_distance", "target": teacher_target,
       "loss_opts": {},
@@ -2173,6 +2174,7 @@ def test_target_with_beam():
   config = Config({
     "debug_print_layer_output_template": True,
     "debug_print_layer_output_shape": True,
+    "debug_runtime_sanity_checks": True,
   })
 
   with make_scope() as session:
@@ -6351,6 +6353,7 @@ def test_cumulated_attention_weights_search():
     "extern_data": {"data": {"dim": n_out, "sparse": True}, "classes": {"dim": n_out, "sparse": True}},
     "search_output_layer": "decision",
     "debug_print_layer_output_shape": True,
+    "debug_runtime_sanity_checks": True,
     "debug_print_layer_output_template": True})
 
   # Try different permutations of the cum_att_energy inputs, previously these behaved differently