Test block headers (#418)

* Block headers tests

* Skip invalid_parent_root test due to https://github.com/status-im/nim-beacon-chain/issues/407

* Fix bls_verify with invalid sig. Activate block header tests

beacon_chain/spec/crypto.nim

@@ -172,7 +172,9 @@ func bls_verify*(
     domain: uint64): bool =
   # name from spec!
   when ValidatorPubKey is BlsValue:
-    doAssert sig.kind == Real and pubkey.kind == Real
+    if sig.kind != Real or pubkey.kind != Real:
+      # TODO: chronicles warning
+      return false
     sig.blsValue.verify(msg, domain, pubkey.blsValue)
   else:
     sig.verify(msg, domain, pubkey)

beacon_chain/spec/state_transition_block.nim

@@ -38,7 +38,7 @@ import # TODO - cleanup imports
   beaconstate, crypto, datatypes, digest, helpers, validator
 
 # https://github.com/ethereum/eth2.0-specs/blob/v0.8.3/specs/core/0_beacon-chain.md#block-header
-proc processBlockHeader(
+proc process_block_header*(
     state: var BeaconState, blck: BeaconBlock, flags: UpdateFlags,
     stateCache: var StateCache): bool =
   # Verify that the slots match
@@ -51,6 +51,8 @@ proc processBlockHeader(
   # Verify that the parent matches
   if skipValidation notin flags and not (blck.parent_root ==
       signing_root(state.latest_block_header)):
+    # TODO: skip validation is too strong
+    #       can't do "invalid_parent_root" test
     notice "Block header: previous block root mismatch",
       latest_block_header = state.latest_block_header,
       blck = shortLog(blck),
@@ -457,7 +459,7 @@ proc processBlock*(
   # TODO when there's a failure, we should reset the state!
   # TODO probably better to do all verification first, then apply state changes
 
-  if not processBlockHeader(state, blck, flags, stateCache):
+  if not process_block_header(state, blck, flags, stateCache):
     notice "Block header not valid", slot = shortLog(state.slot)
     return false
 

tests/official/all_fixtures_require_ssz.nim

@@ -13,4 +13,5 @@ import
   ./test_fixture_sanity_slots,
   ./test_fixture_sanity_blocks,
   ./test_fixture_state_transition_epoch,
-  ./test_fixture_operations_attestations
+  ./test_fixture_operations_attestations,
+  ./test_fixture_operations_block_header

tests/official/test_fixture_operations_block_header.nim

@@ -0,0 +1,73 @@
+# beacon_chain
+# Copyright (c) 2018-Present Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+import
+  # Standard library
+  os, unittest, strutils,
+  # Beacon chain internals
+  ../../beacon_chain/spec/[datatypes, state_transition_block, validator],
+  ../../beacon_chain/[ssz, extras],
+  # Test utilities
+  ../testutil,
+  ./fixtures_utils,
+  ../helpers/debug_state,
+  ../mocking/mock_blocks
+
+const OpBlockHeaderDir = SszTestsDir/const_preset/"phase0"/"operations"/"block_header"/"pyspec_tests"
+
+template runTest(identifier: untyped) =
+  # We wrap the tests in a proc to avoid running out of globals
+  # in the future: Nim supports up to 3500 globals
+  # but unittest with the macro/templates put everything as globals
+  # https://github.com/nim-lang/Nim/issues/12084#issue-486866402
+
+  const testDir = OpBlockHeaderDir / astToStr(identifier)
+
+  proc `testImpl _ blockheader _ identifier`() =
+
+    var flags: UpdateFlags
+    var prefix: string
+    if not existsFile(testDir/"meta.yaml"):
+      flags.incl skipValidation
+    if existsFile(testDir/"post.ssz"):
+      prefix = "[Valid]   "
+    else:
+      prefix = "[Invalid] "
+
+    test prefix & astToStr(identifier):
+      var stateRef, postRef: ref BeaconState
+      var blck: ref BeaconBlock
+      new blck
+      new stateRef
+
+      var cache = get_empty_per_epoch_cache()
+
+      blck[] = parseTest(testDir/"block.ssz", SSZ, BeaconBlock)
+      stateRef[] = parseTest(testDir/"pre.ssz", SSZ, BeaconState)
+
+      if existsFile(testDir/"post.ssz"):
+        new postRef
+        postRef[] = parseTest(testDir/"post.ssz", SSZ, BeaconState)
+
+      if postRef.isNil:
+        let done = process_block_header(stateRef[], blck[], flags, cache)
+        doAssert done == false, "We didn't expect this invalid block header to be processed."
+      else:
+        let done = process_block_header(stateRef[], blck[], flags, cache)
+        doAssert done, "Valid block header not processed"
+        check: stateRef.hash_tree_root() == postRef.hash_tree_root()
+        reportDiff(stateRef, postRef)
+
+  `testImpl _ blockheader _ identifier`()
+
+suite "Official - Operations - Block header " & preset():
+  runTest(success_block_header)
+  runTest(invalid_sig_block_header)
+  runTest(invalid_slot_block_header)
+  when false: # skipValidation needs to be split https://github.com/status-im/nim-beacon-chain/issues/407
+    runTest(invalid_parent_root)
+  runTest(proposer_slashed)