diff --git a/test_libs/pyspec/eth2spec/test/block_processing/test_process_attester_slashing.py b/test_libs/pyspec/eth2spec/test/block_processing/test_process_attester_slashing.py
index ea3a31aea..01861f04c 100644
--- a/test_libs/pyspec/eth2spec/test/block_processing/test_process_attester_slashing.py
+++ b/test_libs/pyspec/eth2spec/test/block_processing/test_process_attester_slashing.py
@@ -46,17 +46,22 @@ def run_attester_slashing_processing(state, attester_slashing, valid=True):
     assert slashed_validator.exit_epoch < spec.FAR_FUTURE_EPOCH
     assert slashed_validator.withdrawable_epoch < spec.FAR_FUTURE_EPOCH
 
-    # lost whistleblower reward
-    assert (
-            get_balance(state, slashed_index) <
-            pre_slashed_balance
-    )
+    if slashed_index != proposer_index:
+        # lost whistleblower reward
+        assert (
+                get_balance(state, slashed_index) <
+                pre_slashed_balance
+        )
 
-    # gained whistleblower reward
-    assert (
-            get_balance(state, proposer_index) >
-            pre_proposer_balance
-    )
+        # gained whistleblower reward
+        assert (
+                get_balance(state, proposer_index) >
+                pre_proposer_balance
+        )
+    else:
+        # gained rewards for all slashings, which may include others. And only lost that of themselves.
+        # Netto at least 0, if more people where slashed, a balance increase.
+        assert get_balance(state, slashed_index) >= pre_slashed_balance
 
     yield 'post', state