diff --git a/test_libs/pyspec/tests/block_processing/test_process_deposit.py b/test_libs/pyspec/tests/block_processing/test_process_deposit.py
index aee9789cd..c45191020 100644
--- a/test_libs/pyspec/tests/block_processing/test_process_deposit.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_deposit.py
@@ -1,4 +1,3 @@
-from copy import deepcopy
 import pytest
 
 import eth2spec.phase0.spec as spec
diff --git a/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py b/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py
index 475221036..fbf4a1959 100644
--- a/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py
+++ b/test_libs/pyspec/tests/block_processing/test_process_proposer_slashing.py
@@ -1,4 +1,3 @@
-from copy import deepcopy
 import pytest
 
 import eth2spec.phase0.spec as spec
@@ -11,78 +10,82 @@ from tests.helpers import (
     get_valid_proposer_slashing,
 )
 
-# mark entire file as 'proposer_slashings'
-pytestmark = pytest.mark.proposer_slashings
+from .block_test_helpers import spec_state_test
 
 
 def run_proposer_slashing_processing(state, proposer_slashing, valid=True):
     """
-    Run ``process_proposer_slashing`` returning the pre and post state.
+    Run ``process_proposer_slashing``, yielding:
+      - pre-state ('pre')
+      - proposer_slashing ('proposer_slashing')
+      - post-state ('post').
     If ``valid == False``, run expecting ``AssertionError``
     """
-    post_state = deepcopy(state)
+    pre_proposer_balance = get_balance(state, proposer_slashing.proposer_index)
+
+    yield 'pre', state
+    yield 'proposer_slashing', proposer_slashing
 
     if not valid:
         with pytest.raises(AssertionError):
-            process_proposer_slashing(post_state, proposer_slashing)
-        return state, None
+            process_proposer_slashing(state, proposer_slashing)
+        yield 'post', None
+        return
 
-    process_proposer_slashing(post_state, proposer_slashing)
+    process_proposer_slashing(state, proposer_slashing)
+    yield 'post', state
 
-    slashed_validator = post_state.validator_registry[proposer_slashing.proposer_index]
+    # check if slashed
+    slashed_validator = state.validator_registry[proposer_slashing.proposer_index]
     assert slashed_validator.slashed
     assert slashed_validator.exit_epoch < spec.FAR_FUTURE_EPOCH
     assert slashed_validator.withdrawable_epoch < spec.FAR_FUTURE_EPOCH
+
     # lost whistleblower reward
     assert (
-        get_balance(post_state, proposer_slashing.proposer_index) <
-        get_balance(state, proposer_slashing.proposer_index)
+        get_balance(state, proposer_slashing.proposer_index) <
+        pre_proposer_balance
     )
 
-    return state, post_state
-
 
+@spec_state_test
 def test_success(state):
     proposer_slashing = get_valid_proposer_slashing(state)
 
-    pre_state, post_state = run_proposer_slashing_processing(state, proposer_slashing)
-
-    return pre_state, proposer_slashing, post_state
+    yield from run_proposer_slashing_processing(state, proposer_slashing)
 
 
+@spec_state_test
 def test_epochs_are_different(state):
     proposer_slashing = get_valid_proposer_slashing(state)
 
     # set slots to be in different epochs
     proposer_slashing.header_2.slot += spec.SLOTS_PER_EPOCH
 
-    pre_state, post_state = run_proposer_slashing_processing(state, proposer_slashing, False)
-
-    return pre_state, proposer_slashing, post_state
+    yield from run_proposer_slashing_processing(state, proposer_slashing, False)
 
 
+@spec_state_test
 def test_headers_are_same(state):
     proposer_slashing = get_valid_proposer_slashing(state)
 
     # set headers to be the same
     proposer_slashing.header_2 = proposer_slashing.header_1
 
-    pre_state, post_state = run_proposer_slashing_processing(state, proposer_slashing, False)
-
-    return pre_state, proposer_slashing, post_state
+    yield from run_proposer_slashing_processing(state, proposer_slashing, False)
 
 
+@spec_state_test
 def test_proposer_is_slashed(state):
     proposer_slashing = get_valid_proposer_slashing(state)
 
     # set proposer to slashed
     state.validator_registry[proposer_slashing.proposer_index].slashed = True
 
-    pre_state, post_state = run_proposer_slashing_processing(state, proposer_slashing, False)
-
-    return pre_state, proposer_slashing, post_state
+    yield from run_proposer_slashing_processing(state, proposer_slashing, False)
 
 
+@spec_state_test
 def test_proposer_is_withdrawn(state):
     proposer_slashing = get_valid_proposer_slashing(state)
 
@@ -91,6 +94,4 @@ def test_proposer_is_withdrawn(state):
     proposer_index = proposer_slashing.proposer_index
     state.validator_registry[proposer_index].withdrawable_epoch = current_epoch - 1
 
-    pre_state, post_state = run_proposer_slashing_processing(state, proposer_slashing, False)
-
-    return pre_state, proposer_slashing, post_state
+    yield from run_proposer_slashing_processing(state, proposer_slashing, False)