diff --git a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
index d92220910..6c1319a5b 100644
--- a/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
+++ b/test_libs/pyspec/eth2spec/test/phase_0/epoch_processing/test_process_registry_updates.py
@@ -30,18 +30,20 @@ def run_process_registry_updates(spec, state, valid=True):
     yield 'post', state
 
 
-@with_all_phases
-@spec_state_test
-def test_activation(spec, state):
-    index = 0
+def mock_deposit(spec, state, index):
     assert spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
-
-    # Mock a new deposit
     state.validators[index].activation_eligibility_epoch = spec.FAR_FUTURE_EPOCH
     state.validators[index].activation_epoch = spec.FAR_FUTURE_EPOCH
     state.validators[index].effective_balance = spec.MAX_EFFECTIVE_BALANCE
     assert not spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
 
+
+@with_all_phases
+@spec_state_test
+def test_activation(spec, state):
+    index = 0
+    mock_deposit(spec, state, index)
+
     for _ in range(spec.ACTIVATION_EXIT_DELAY + 1):
         next_epoch(spec, state)
 
@@ -49,10 +51,39 @@ def test_activation(spec, state):
 
     assert state.validators[index].activation_eligibility_epoch != spec.FAR_FUTURE_EPOCH
     assert state.validators[index].activation_epoch != spec.FAR_FUTURE_EPOCH
-    assert spec.is_active_validator(
-        state.validators[index],
-        spec.get_current_epoch(state),
-    )
+    assert spec.is_active_validator(state.validators[index], spec.get_current_epoch(state))
+
+
+@with_all_phases
+@spec_state_test
+def test_activation_queue_sorting(spec, state):
+    mock_activations = 10
+
+    epoch = spec.get_current_epoch(state)
+    for i in range(mock_activations):
+        mock_deposit(spec, state, i)
+        state.validators[i].activation_eligibility_epoch = epoch + 1
+
+    # give the last priority over the others
+    state.validators[mock_activations - 1].activation_eligibility_epoch = epoch
+
+    # make sure we are hitting the churn
+    churn_limit = spec.get_churn_limit(state)
+    assert mock_activations > churn_limit
+
+    yield from run_process_registry_updates(spec, state)
+
+    # the first got in as second
+    assert state.validators[0].activation_epoch != spec.FAR_FUTURE_EPOCH
+    # the prioritized got in as first
+    assert state.validators[mock_activations - 1].activation_epoch != spec.FAR_FUTURE_EPOCH
+    # the second last is at the end of the queue, and did not make the churn,
+    #  hence is not assigned an activation_epoch yet.
+    assert state.validators[mock_activations - 2].activation_epoch == spec.FAR_FUTURE_EPOCH
+    # the one at churn_limit - 1 did not make it, it was out-prioritized
+    assert state.validators[churn_limit - 1].activation_epoch == spec.FAR_FUTURE_EPOCH
+    # but the the one in front of the above did
+    assert state.validators[churn_limit - 2].activation_epoch != spec.FAR_FUTURE_EPOCH
 
 
 @with_all_phases