update epoch processing tests to conform to processing pattern, add docs for epoch sub-transition testing

specs/test_formats/epoch_processing/README.md

@@ -0,0 +1,34 @@
+# Epoch processing tests
+
+The different epoch sub-transitions are tested individually with test handlers.
+The format is similar to block-processing state-transition tests.
+There is no "change" factor however, the transitions are a pure functions with just the pre-state as input.
+Hence, the format is shared between each test-handler. (See test condition documentation on how to run the tests.)
+
+## Test case format
+
+```yaml
+description: string    -- description of test case, purely for debugging purposes
+bls_required: bool     -- optional, true if the test validity is strictly dependent on BLS being ON. False otherwise.
+bls_ignored: bool      -- optional, true if the test validity is strictly dependent on BLS being OFF. False otherwise.
+pre: BeaconState       -- state before running the sub-transition
+post: BeaconState      -- state after applying the epoch sub-transition.
+```
+
+Note: if both `bls_required` and `bls_ignored` are false (or simply not included),
+ then the test consumer can freely choose to run with BLS ON or OFF.
+One may choose for OFF for performance reasons during repeated testing. Otherwise it is recommended to run with BLS ON.
+
+## Condition
+
+A handler of the `epoch_processing` test-runner should process these cases, 
+ calling the corresponding processing implementation.
+
+Sub-transitions:
+
+| *`sub-transition-name`* | *`processing call`*               |
+|-------------------------|-----------------------------------|
+| `crosslinks`            | `process_crosslinks(state)`       |
+| `registry_updates`      | `process_registry_updates(state)` |
+
+The resulting state should match the expected `post` state.

test_libs/pyspec/eth2spec/test/epoch_processing/test_process_registry_updates.py

@@ -3,8 +3,8 @@ import eth2spec.phase0.spec as spec
 from eth2spec.phase0.spec import (
     get_current_epoch,
     is_active_validator,
+    process_registry_updates
 )
-from eth2spec.test.helpers.block import apply_empty_block
 from eth2spec.test.helpers.state import next_epoch
 from eth2spec.test.context import spec_state_test
 
@@ -20,13 +20,12 @@ def test_activation(state):
     state.validator_registry[index].effective_balance = spec.MAX_EFFECTIVE_BALANCE
     assert not is_active_validator(state.validator_registry[index], get_current_epoch(state))
 
-    for _ in range(spec.ACTIVATION_EXIT_DELAY):
+    for _ in range(spec.ACTIVATION_EXIT_DELAY + 1):
         next_epoch(state)
 
     yield 'pre', state
 
-    next_epoch(state)
+    process_registry_updates(state)
-    yield 'trigger_block', apply_empty_block(state)
 
     yield 'post', state
 
@@ -47,13 +46,12 @@ def test_ejection(state):
     # Mock an ejection
     state.validator_registry[index].effective_balance = spec.EJECTION_BALANCE
 
-    for _ in range(spec.ACTIVATION_EXIT_DELAY):
+    for _ in range(spec.ACTIVATION_EXIT_DELAY + 1):
         next_epoch(state)
 
     yield 'pre', state
 
-    next_epoch(state)
+    process_registry_updates(state)
-    yield 'trigger_block', apply_empty_block(state)
 
     yield 'post', state