diff --git a/Jenkinsfile b/Jenkinsfile
index f8da394af..4055335a6 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -1,26 +1,42 @@
 def runStages() {
-	stage("Clone") {
-		/* The Git repo seems to be cached in some Jenkins plugin, so this is not always a clean clone. */
-		checkout scm
-		sh "make build-system-checks || true"
-	}
-	stage("Build") {
-		sh "make -j${env.NPROC} update" /* to allow a newer Nim version to be detected */
-		sh "make -j${env.NPROC} V=1 deps" /* to allow the following parallel stages */
-	}
-	stage("Test") {
-		parallel(
-			"tools": {
-				stage("Tools") {
-					sh "make -j${env.NPROC}"
-				}
-			},
-			"test suite": {
-				stage("Test suite") {
-					sh "make -j${env.NPROC} test"
-				}
+	try {
+		stage("Clone") {
+			checkout scm
+			sh "make build-system-checks || true"
+		}
+
+		cache(maxCacheSize: 250, caches: [
+			[$class: "ArbitraryFileCache", excludes: "", includes: "**/*", path: "${WORKSPACE}/vendor/nimbus-build-system/vendor/Nim/bin"],
+			[$class: "ArbitraryFileCache", excludes: "", includes: "**/*", path: "${WORKSPACE}/vendor/go/bin"],
+			[$class: "ArbitraryFileCache", excludes: "", includes: "**/*", path: "${WORKSPACE}/jsonTestsCache"]
+		]) {
+			stage("Build") {
+				sh "make -j${env.NPROC} update" /* to allow a newer Nim version to be detected */
+				sh "make -j${env.NPROC} deps" /* to allow the following parallel stages */
+				sh "scripts/setup_official_tests.sh jsonTestsCache"
 			}
-		)
+		}
+
+		stage("Test") {
+			parallel(
+				"tools": {
+					stage("Tools") {
+						sh "make -j${env.NPROC}"
+					}
+				},
+				"test suite": {
+					stage("Test suite") {
+						sh "make -j${env.NPROC} DISABLE_TEST_FIXTURES_SCRIPT=1 test"
+					}
+				}
+			)
+		}
+	} catch(e) {
+		echo "'${env.STAGE_NAME}' stage failed"
+		// we need to rethrow the exception here
+		throw e
+	} finally {
+		cleanWs()
 	}
 }
 
diff --git a/Makefile b/Makefile
index e3ada862f..77c2e833e 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,12 @@ TOOLS_CSV := $(subst $(SPACE),$(COMMA),$(TOOLS))
 
 .PHONY: all build-system-checks deps update p2pd test $(TOOLS) clean_eth2_network_simulation_files eth2_network_simulation clean-testnet0 testnet0 clean-testnet1 testnet1 clean
 
+ifeq ($(NIM_PARAMS),)
+# "variables.mk" was not included. We can only execute one target in this state.
+all: | build-system-checks
+else
 all: | build-system-checks $(TOOLS)
+endif
 
 # must be included after the default target
 -include $(BUILD_SYSTEM_DIR)/makefiles/targets.mk
@@ -29,9 +34,11 @@ build-system-checks:
 	@[[ -e "$(BUILD_SYSTEM_DIR)/makefiles" ]] || { \
 		echo -e "'$(BUILD_SYSTEM_DIR)/makefiles' not found. Running '$(GIT_SUBMODULE_UPDATE)'.\n"; \
 		$(GIT_SUBMODULE_UPDATE); \
-		echo -e "\nYou can now run '$(MAKE)' again."; \
-		exit 1; \
-		}
+		CHECKMARK="\xe2\x9c\x94\xef\xb8\x8f"; \
+		echo -e "\n$${CHECKMARK}$${CHECKMARK}$${CHECKMARK} Successfully fetched all required internal dependencies."; \
+		echo -e "        You should now \e[4mre-run '$(MAKE)' to build Nimbus\e[0m\n"; \
+		}; \
+		exit 0
 
 deps: | deps-common beacon_chain.nims p2pd
 
diff --git a/README.md b/README.md
index 465103551..d93c522da 100644
--- a/README.md
+++ b/README.md
@@ -98,8 +98,8 @@ Once the [prerequisites](#prerequisites) are installed you can connect to testne
 git clone https://github.com/status-im/nim-beacon-chain
 cd nim-beacon-chain
 make                 # This invocation will bootstrap the build system with additional Makefiles
-make update deps     # This will build Nim and all other dependencies
-./connect-to-testnet testnet0
+make testnet0        # This will build Nimbus and all other dependencies
+                     # and connect you to testnet0
 ```
 
 The testnets are restarted once per week, usually on Monday evenings (UTC)) and integrate the changes for the past week.
diff --git a/nfuzz/README.md b/nfuzz/README.md
index aa9df3e05..8ca9e3a40 100644
--- a/nfuzz/README.md
+++ b/nfuzz/README.md
@@ -26,6 +26,7 @@ additional Nim arguments, e.g.:
 ```bash
 make libnfuzz.a NIMFLAGS="--cc:clang --passC:'-fsanitize=fuzzer' --passL='-fsanitize=fuzzer'"
 ```
+To disable BLS verification on deserialization of SSZ objects add `-d:ssz_testing` to the NIMFLAGS.
 
 Other useful options might include: `--clang.path:<path>`, `--clang.exe:<exe>`, `--clang.linkerexe:<exe>`.
 
diff --git a/research/state_sim.nim b/research/state_sim.nim
index e7dc2be63..9acdb2981 100644
--- a/research/state_sim.nim
+++ b/research/state_sim.nim
@@ -1,8 +1,8 @@
 import
-  confutils, stats, times,
+  confutils, stats, times, std/monotimes,
   strformat,
   options, sequtils, random, tables,
-  ../tests/[testutil],
+  ../tests/[testutil, testblockutil],
   ../beacon_chain/spec/[beaconstate, crypto, datatypes, digest, helpers, validator],
   ../beacon_chain/[attestation_pool, extras, ssz]
 
@@ -13,24 +13,6 @@ type Timers = enum
   tShuffle = "Retrieve committee once using get_beacon_committee"
   tAttest = "Combine committee attestations"
 
-template withTimer(stats: var RunningStat, body: untyped) =
-  let start = cpuTime()
-
-  block:
-    body
-
-  let stop = cpuTime()
-  stats.push stop - start
-
-template withTimerRet(stats: var RunningStat, body: untyped): untyped =
-  let start = cpuTime()
-  let tmp = block:
-    body
-  let stop = cpuTime()
-  stats.push stop - start
-
-  tmp
-
 proc writeJson*(prefix, slot, v: auto) =
   var f: File
   defer: close(f)
@@ -54,7 +36,7 @@ func verifyConsensus(state: BeaconState, attesterRatio: auto) =
     doAssert state.finalized_checkpoint.epoch + 2 >= current_epoch
 
 cli do(slots = SLOTS_PER_EPOCH * 6,
-       validators = SLOTS_PER_EPOCH * 11, # One per shard is minimum
+       validators = SLOTS_PER_EPOCH * 30, # One per shard is minimum
        json_interval = SLOTS_PER_EPOCH,
        prefix = 0,
        attesterRatio {.desc: "ratio of validators that attest in each round"} = 0.73,
diff --git a/tests/test_attestation_pool.nim b/tests/test_attestation_pool.nim
index 050238a0d..aca42ca79 100644
--- a/tests/test_attestation_pool.nim
+++ b/tests/test_attestation_pool.nim
@@ -10,7 +10,7 @@
 import
   options, unittest,
   chronicles,
-  ./testutil,
+  ./testutil, ./testblockutil,
   ../beacon_chain/spec/[beaconstate, crypto, datatypes, digest, helpers, validator],
   ../beacon_chain/[beacon_node_types, attestation_pool, block_pool, extras, state_transition, ssz]
 
diff --git a/tests/test_beacon_chain_db.nim b/tests/test_beacon_chain_db.nim
index 35bbfa4fe..d6858f0bb 100644
--- a/tests/test_beacon_chain_db.nim
+++ b/tests/test_beacon_chain_db.nim
@@ -11,7 +11,7 @@ import  options, unittest, sequtils, eth/trie/[db],
   ../beacon_chain/[beacon_chain_db, extras, interop, ssz],
   ../beacon_chain/spec/[beaconstate, datatypes, digest, crypto],
   # test utilies
-  ./testutil
+  ./testutil, ./testblockutil
 
 suite "Beacon chain DB" & preset():
 
diff --git a/tests/test_beaconstate.nim b/tests/test_beaconstate.nim
index 4cb3be36d..09ca42bfb 100644
--- a/tests/test_beaconstate.nim
+++ b/tests/test_beaconstate.nim
@@ -9,7 +9,7 @@
 
 import
   unittest,
-  ./testutil,
+  ./testutil, ./testblockutil,
   ../beacon_chain/spec/[beaconstate, datatypes, digest]
 
 suite "Beacon state" & preset():
diff --git a/tests/test_block_pool.nim b/tests/test_block_pool.nim
index b1b154c27..3e70a006d 100644
--- a/tests/test_block_pool.nim
+++ b/tests/test_block_pool.nim
@@ -9,7 +9,7 @@
 
 import
   options, sequtils, unittest,
-  ./testutil,
+  ./testutil, ./testblockutil,
   ../beacon_chain/spec/[beaconstate, datatypes, digest],
   ../beacon_chain/[beacon_node_types, block_pool, beacon_chain_db, extras, ssz]
 
diff --git a/tests/test_state_transition.nim b/tests/test_state_transition.nim
index 10a2e5c82..ec4a47071 100644
--- a/tests/test_state_transition.nim
+++ b/tests/test_state_transition.nim
@@ -9,7 +9,7 @@
 
 import
   unittest,
-  ./testutil,
+  ./testutil, ./testblockutil,
   ../beacon_chain/spec/[beaconstate, datatypes, digest, validator],
   ../beacon_chain/[state_transition, ssz]
 
diff --git a/tests/testblockutil.nim b/tests/testblockutil.nim
new file mode 100644
index 000000000..d59bc7182
--- /dev/null
+++ b/tests/testblockutil.nim
@@ -0,0 +1,207 @@
+# beacon_chain
+# Copyright (c) 2018-2019 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://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
+  stew/endians2,
+  chronicles, eth/trie/[db],
+  ../beacon_chain/[beacon_chain_db, block_pool, extras, ssz, state_transition,
+    validator_pool],
+  ../beacon_chain/spec/[beaconstate, crypto, datatypes, digest,
+    helpers, validator]
+
+when ValidatorPrivKey is BlsValue:
+  func makeFakeValidatorPrivKey(i: int): ValidatorPrivKey =
+    # 0 is not a valid BLS private key - 1000 helps interop with rust BLS library,
+    # lighthouse.
+    # TODO: switch to https://github.com/ethereum/eth2.0-pm/issues/60
+    result.kind = BlsValueType.Real
+    var bytes = uint64(i + 1000).toBytesLE()
+    copyMem(addr result.blsValue.x[0], addr bytes[0], sizeof(bytes))
+else:
+  func makeFakeValidatorPrivKey(i: int): ValidatorPrivKey =
+    # 0 is not a valid BLS private key - 1000 helps interop with rust BLS library,
+    # lighthouse.
+    # TODO: switch to https://github.com/ethereum/eth2.0-pm/issues/60
+    var bytes = uint64(i + 1000).toBytesLE()
+    copyMem(addr result.x[0], addr bytes[0], sizeof(bytes))
+
+func makeFakeHash(i: int): Eth2Digest =
+  var bytes = uint64(i).toBytesLE()
+  static: doAssert sizeof(bytes) <= sizeof(result.data)
+  copyMem(addr result.data[0], addr bytes[0], sizeof(bytes))
+
+func hackPrivKey(v: Validator): ValidatorPrivKey =
+  ## Extract private key, per above hack
+  var bytes: array[8, byte]
+  static: doAssert sizeof(bytes) <= sizeof(v.withdrawal_credentials.data)
+
+  copyMem(
+    addr bytes, unsafeAddr v.withdrawal_credentials.data[0], sizeof(bytes))
+  let i = int(uint64.fromBytesLE(bytes))
+  makeFakeValidatorPrivKey(i)
+
+func makeDeposit(i: int, flags: UpdateFlags): Deposit =
+  ## Ugly hack for now: we stick the private key in withdrawal_credentials
+  ## which means we can repro private key and randao reveal from this data,
+  ## for testing :)
+  let
+    privkey = makeFakeValidatorPrivKey(i)
+    pubkey = privkey.pubKey()
+    withdrawal_credentials = makeFakeHash(i)
+    domain = compute_domain(DOMAIN_DEPOSIT)
+
+  result = Deposit(
+    data: DepositData(
+      pubkey: pubkey,
+      withdrawal_credentials: withdrawal_credentials,
+      amount: MAX_EFFECTIVE_BALANCE,
+    )
+  )
+
+  if skipValidation notin flags:
+    result.data.signature =
+      bls_sign(privkey, signing_root(result.data).data,
+               domain)
+
+func makeInitialDeposits*(
+    n = SLOTS_PER_EPOCH, flags: UpdateFlags = {}): seq[Deposit] =
+  for i in 0..<n.int:
+    result.add makeDeposit(i, flags)
+
+proc addBlock*(
+    state: var BeaconState, previous_block_root: Eth2Digest,
+    body: BeaconBlockBody, flags: UpdateFlags = {}): BeaconBlock =
+  # Create and add a block to state - state will advance by one slot!
+  # This is the equivalent of running
+  # updateState(state, prev_block, makeBlock(...), {skipValidation})
+  # but avoids some slow block copies
+
+  state.slot += 1
+  var cache = get_empty_per_epoch_cache()
+  let proposer_index = get_beacon_proposer_index(state, cache)
+  state.slot -= 1
+
+  let
+    # Index from the new state, but registry from the old state.. hmm...
+    proposer = state.validators[proposer_index]
+    privKey = hackPrivKey(proposer)
+
+  # TODO ugly hack; API needs rethinking
+  var new_body = body
+  new_body.randao_reveal = privKey.genRandaoReveal(state.fork, state.slot + 1)
+  new_body.eth1_data = Eth1Data()
+
+  var
+    # In order to reuse the state transition function, we first create a dummy
+    # block that has some fields set, and use that to generate the state as it
+    # would look with the new block applied.
+    new_block = BeaconBlock(
+      slot: state.slot + 1,
+      parent_root: previous_block_root,
+      state_root: Eth2Digest(), # we need the new state first
+      body: new_body,
+      signature: ValidatorSig(), # we need the rest of the block first!
+    )
+
+  let block_ok = state_transition(state, new_block, {skipValidation})
+  doAssert block_ok
+
+  # Ok, we have the new state as it would look with the block applied - now we
+  # can set the state root in order to be able to create a valid signature
+  new_block.state_root = hash_tree_root(state)
+
+  doAssert privKey.pubKey() == proposer.pubkey,
+    "signature key should be derived from private key! - wrong privkey?"
+
+  if skipValidation notin flags:
+    let block_root = signing_root(new_block)
+    # We have a signature - put it in the block and we should be done!
+    new_block.signature =
+      bls_sign(privKey, block_root.data,
+               get_domain(state, DOMAIN_BEACON_PROPOSER,
+               compute_epoch_at_slot(new_block.slot)))
+
+    doAssert bls_verify(
+      proposer.pubkey,
+      block_root.data, new_block.signature,
+      get_domain(
+        state, DOMAIN_BEACON_PROPOSER, compute_epoch_at_slot(new_block.slot))),
+      "we just signed this message - it should pass verification!"
+
+  new_block
+
+proc makeBlock*(
+    state: BeaconState, previous_block_root: Eth2Digest,
+    body: BeaconBlockBody): BeaconBlock =
+  # Create a block for `state.slot + 1` - like a block proposer would do!
+  # It's a bit awkward - in order to produce a block for N+1, we need to
+  # calculate what the state will look like after that block has been applied,
+  # because the block includes the state root.
+  var next_state = state
+  addBlock(next_state, previous_block_root, body)
+
+proc makeAttestation*(
+    state: BeaconState, beacon_block_root: Eth2Digest,
+    committee: seq[ValidatorIndex], slot: Slot, index: uint64,
+    validator_index: auto, cache: var StateCache,
+    flags: UpdateFlags = {}): Attestation =
+  # Avoids state_sim silliness; as it's responsible for all validators,
+  # transforming, from monotonic enumerable index -> committee index ->
+  # montonoic enumerable index, is wasteful and slow. Most test callers
+  # want ValidatorIndex, so that's supported too.
+  let
+    validator = state.validators[validator_index]
+    sac_index = committee.find(validator_index)
+    data = makeAttestationData(state, slot, index, beacon_block_root)
+
+  doAssert sac_index != -1, "find_beacon_committee should guarantee this"
+
+  var aggregation_bits = CommitteeValidatorsBits.init(committee.len)
+  aggregation_bits.raiseBit sac_index
+
+  let
+    msg = hash_tree_root(data)
+    sig =
+      if skipValidation notin flags:
+        bls_sign(
+          hackPrivKey(validator), @(msg.data),
+          get_domain(
+            state,
+            DOMAIN_BEACON_ATTESTER,
+            data.target.epoch))
+      else:
+        ValidatorSig()
+
+  Attestation(
+    data: data,
+    aggregation_bits: aggregation_bits,
+    signature: sig
+  )
+
+proc find_beacon_committee(
+    state: BeaconState, validator_index: ValidatorIndex,
+    cache: var StateCache): auto =
+  let epoch = compute_epoch_at_slot(state.slot)
+  for epoch_committee_index in 0'u64 ..< get_committee_count_at_slot(
+      state, epoch.compute_start_slot_at_epoch) * SLOTS_PER_EPOCH:
+    let
+      slot = ((epoch_committee_index mod SLOTS_PER_EPOCH) +
+        epoch.compute_start_slot_at_epoch.uint64).Slot
+      index = epoch_committee_index div SLOTS_PER_EPOCH
+      committee = get_beacon_committee(state, slot, index, cache)
+    if validator_index in committee:
+      return (committee, slot, index)
+  doAssert false
+
+proc makeAttestation*(
+    state: BeaconState, beacon_block_root: Eth2Digest,
+    validator_index: ValidatorIndex, cache: var StateCache,
+    flags: UpdateFlags = {}): Attestation =
+  let (committee, slot, index) =
+    find_beacon_committee(state, validator_index, cache)
+  makeAttestation(state, beacon_block_root, committee, slot, index,
+    validator_index, cache, flags)
diff --git a/tests/testutil.nim b/tests/testutil.nim
index dcdc6eeac..10a8c577b 100644
--- a/tests/testutil.nim
+++ b/tests/testutil.nim
@@ -6,208 +6,31 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
-  options, stew/endians2,
+  stats, stew/endians2,
   chronicles, eth/trie/[db],
-  ../beacon_chain/[beacon_chain_db, block_pool, extras, ssz, state_transition,
-    validator_pool, beacon_node_types],
-  ../beacon_chain/spec/[beaconstate, crypto, datatypes, digest,
-    helpers, validator]
+  ../beacon_chain/[beacon_chain_db, block_pool, ssz, beacon_node_types],
+  ../beacon_chain/spec/datatypes
 
 func preset*(): string =
   " [Preset: " & const_preset & ']'
 
-when ValidatorPrivKey is BlsValue:
-  func makeFakeValidatorPrivKey(i: int): ValidatorPrivKey =
-    # 0 is not a valid BLS private key - 1000 helps interop with rust BLS library,
-    # lighthouse.
-    # TODO: switch to https://github.com/ethereum/eth2.0-pm/issues/60
-    result.kind = BlsValueType.Real
-    var bytes = uint64(i + 1000).toBytesLE()
-    copyMem(addr result.blsValue.x[0], addr bytes[0], sizeof(bytes))
-else:
-  func makeFakeValidatorPrivKey(i: int): ValidatorPrivKey =
-    # 0 is not a valid BLS private key - 1000 helps interop with rust BLS library,
-    # lighthouse.
-    # TODO: switch to https://github.com/ethereum/eth2.0-pm/issues/60
-    var bytes = uint64(i + 1000).toBytesLE()
-    copyMem(addr result.x[0], addr bytes[0], sizeof(bytes))
+template withTimer*(stats: var RunningStat, body: untyped) =
+  let start = getMonoTime()
 
-func makeFakeHash(i: int): Eth2Digest =
-  var bytes = uint64(i).toBytesLE()
-  static: doAssert sizeof(bytes) <= sizeof(result.data)
-  copyMem(addr result.data[0], addr bytes[0], sizeof(bytes))
+  block:
+    body
 
-func hackPrivKey(v: Validator): ValidatorPrivKey =
-  ## Extract private key, per above hack
-  var bytes: array[8, byte]
-  static: doAssert sizeof(bytes) <= sizeof(v.withdrawal_credentials.data)
+  let stop = getMonoTime()
+  stats.push (stop - start).inMicroseconds.float / 1000000.0
 
-  copyMem(
-    addr bytes, unsafeAddr v.withdrawal_credentials.data[0], sizeof(bytes))
-  let i = int(uint64.fromBytesLE(bytes))
-  makeFakeValidatorPrivKey(i)
+template withTimerRet*(stats: var RunningStat, body: untyped): untyped =
+  let start = getMonoTime()
+  let tmp = block:
+    body
+  let stop = getMonoTime()
+  stats.push (stop - start).inMicroseconds.float / 1000000.0
 
-func makeDeposit(i: int, flags: UpdateFlags): Deposit =
-  ## Ugly hack for now: we stick the private key in withdrawal_credentials
-  ## which means we can repro private key and randao reveal from this data,
-  ## for testing :)
-  let
-    privkey = makeFakeValidatorPrivKey(i)
-    pubkey = privkey.pubKey()
-    withdrawal_credentials = makeFakeHash(i)
-    domain = compute_domain(DOMAIN_DEPOSIT)
-
-  result = Deposit(
-    data: DepositData(
-      pubkey: pubkey,
-      withdrawal_credentials: withdrawal_credentials,
-      amount: MAX_EFFECTIVE_BALANCE,
-    )
-  )
-
-  if skipValidation notin flags:
-    result.data.signature =
-      bls_sign(privkey, signing_root(result.data).data,
-               domain)
-
-func makeInitialDeposits*(
-    n = SLOTS_PER_EPOCH, flags: UpdateFlags = {}): seq[Deposit] =
-  for i in 0..<n.int:
-    result.add makeDeposit(i, flags)
-
-proc addBlock*(
-    state: var BeaconState, previous_block_root: Eth2Digest,
-    body: BeaconBlockBody, flags: UpdateFlags = {}): BeaconBlock =
-  # Create and add a block to state - state will advance by one slot!
-  # This is the equivalent of running
-  # updateState(state, prev_block, makeBlock(...), {skipValidation})
-  # but avoids some slow block copies
-
-  state.slot += 1
-  var cache = get_empty_per_epoch_cache()
-  let proposer_index = get_beacon_proposer_index(state, cache)
-  state.slot -= 1
-
-  let
-    # Index from the new state, but registry from the old state.. hmm...
-    proposer = state.validators[proposer_index]
-    privKey = hackPrivKey(proposer)
-
-  # TODO ugly hack; API needs rethinking
-  var new_body = body
-  new_body.randao_reveal = privKey.genRandaoReveal(state.fork, state.slot + 1)
-  new_body.eth1_data = Eth1Data()
-
-  var
-    # In order to reuse the state transition function, we first create a dummy
-    # block that has some fields set, and use that to generate the state as it
-    # would look with the new block applied.
-    new_block = BeaconBlock(
-      slot: state.slot + 1,
-      parent_root: previous_block_root,
-      state_root: Eth2Digest(), # we need the new state first
-      body: new_body,
-      signature: ValidatorSig(), # we need the rest of the block first!
-    )
-
-  let block_ok = state_transition(state, new_block, {skipValidation})
-  doAssert block_ok
-
-  # Ok, we have the new state as it would look with the block applied - now we
-  # can set the state root in order to be able to create a valid signature
-  new_block.state_root = hash_tree_root(state)
-
-  doAssert privKey.pubKey() == proposer.pubkey,
-    "signature key should be derived from private key! - wrong privkey?"
-
-  if skipValidation notin flags:
-    let block_root = signing_root(new_block)
-    # We have a signature - put it in the block and we should be done!
-    new_block.signature =
-      bls_sign(privKey, block_root.data,
-               get_domain(state, DOMAIN_BEACON_PROPOSER,
-               compute_epoch_at_slot(new_block.slot)))
-
-    doAssert bls_verify(
-      proposer.pubkey,
-      block_root.data, new_block.signature,
-      get_domain(
-        state, DOMAIN_BEACON_PROPOSER, compute_epoch_at_slot(new_block.slot))),
-      "we just signed this message - it should pass verification!"
-
-  new_block
-
-proc makeBlock*(
-    state: BeaconState, previous_block_root: Eth2Digest,
-    body: BeaconBlockBody): BeaconBlock =
-  # Create a block for `state.slot + 1` - like a block proposer would do!
-  # It's a bit awkward - in order to produce a block for N+1, we need to
-  # calculate what the state will look like after that block has been applied,
-  # because the block includes the state root.
-  var next_state = state
-  addBlock(next_state, previous_block_root, body)
-
-proc find_beacon_committee(
-    state: BeaconState, validator_index: ValidatorIndex,
-    cache: var StateCache): auto =
-  let epoch = compute_epoch_at_slot(state.slot)
-  for epoch_committee_index in 0'u64 ..< get_committee_count_at_slot(
-      state, epoch.compute_start_slot_at_epoch) * SLOTS_PER_EPOCH:
-    let
-      slot = ((epoch_committee_index mod SLOTS_PER_EPOCH) +
-        epoch.compute_start_slot_at_epoch.uint64).Slot
-      index = epoch_committee_index div SLOTS_PER_EPOCH
-      committee = get_beacon_committee(state, slot, index, cache)
-    if validator_index in committee:
-      return (committee, slot, index)
-  doAssert false
-
-proc makeAttestation*(
-    state: BeaconState, beacon_block_root: Eth2Digest,
-    committee: seq[ValidatorIndex], slot: Slot, index: uint64,
-    validator_index: auto, cache: var StateCache,
-    flags: UpdateFlags = {}): Attestation =
-  # Avoids state_sim silliness; as it's responsible for all validators,
-  # transforming, from monotonic enumerable index -> committee index ->
-  # montonoic enumerable index, is wasteful and slow. Most test callers
-  # want ValidatorIndex, so that's supported too.
-  let
-    validator = state.validators[validator_index]
-    sac_index = committee.find(validator_index)
-    data = makeAttestationData(state, slot, index, beacon_block_root)
-
-  doAssert sac_index != -1, "find_beacon_committee should guarantee this"
-
-  var aggregation_bits = CommitteeValidatorsBits.init(committee.len)
-  aggregation_bits.raiseBit sac_index
-
-  let
-    msg = hash_tree_root(data)
-    sig =
-      if skipValidation notin flags:
-        bls_sign(
-          hackPrivKey(validator), @(msg.data),
-          get_domain(
-            state,
-            DOMAIN_BEACON_ATTESTER,
-            data.target.epoch))
-      else:
-        ValidatorSig()
-
-  Attestation(
-    data: data,
-    aggregation_bits: aggregation_bits,
-    signature: sig
-  )
-
-proc makeAttestation*(
-    state: BeaconState, beacon_block_root: Eth2Digest,
-    validator_index: ValidatorIndex, cache: var StateCache,
-    flags: UpdateFlags = {}): Attestation =
-  let (committee, slot, index) =
-    find_beacon_committee(state, validator_index, cache)
-  makeAttestation(state, beacon_block_root, committee, slot, index,
-    validator_index, cache, flags)
+  tmp
 
 proc makeTestDB*(tailState: BeaconState, tailBlock: BeaconBlock): BeaconChainDB =
   result = init(BeaconChainDB, newMemoryDB())
diff --git a/vendor/nimbus-build-system b/vendor/nimbus-build-system
index 42c5e97a5..6cfabf782 160000
--- a/vendor/nimbus-build-system
+++ b/vendor/nimbus-build-system
@@ -1 +1 @@
-Subproject commit 42c5e97a5ba2cf31a573160e7d0a2efd615334c5
+Subproject commit 6cfabf7820834cb99bd30fc664d3ab91eb0493bf