diff --git a/tests/mocking/mock_blocks.nim b/tests/mocking/mock_blocks.nim
index f5969092c..0893161ad 100644
--- a/tests/mocking/mock_blocks.nim
+++ b/tests/mocking/mock_blocks.nim
@@ -45,14 +45,17 @@ proc signMockBlock*(state: ForkedHashedBeaconState, b: var ForkedSignedBeaconBlo
         privkey).toValidatorSig()
 
 # https://github.com/ethereum/consensus-specs/blob/v1.1.0-beta.4/tests/core/pyspec/eth2spec/test/helpers/block.py#L75-L105
-proc mockBlock*(state: ForkedHashedBeaconState, slot: Slot): ForkedSignedBeaconBlock =
+proc mockBlock*(
+    state: ForkedHashedBeaconState, 
+    slot: Slot, 
+    cfg = defaultRuntimeConfig): ForkedSignedBeaconBlock =
   ## TODO don't do this gradual construction, for exception safety
   ## Mock a BeaconBlock for the specific slot
 
   var cache = StateCache()
   var rewards = RewardInfo()
   var tmpState = assignClone(state)
-  doAssert process_slots(defaultRuntimeConfig, tmpState[], slot, cache, rewards, flags = {})
+  doAssert process_slots(cfg, tmpState[], slot, cache, rewards, flags = {})
   
   var previous_block_header = getStateField(tmpState[], latest_block_header)
   if previous_block_header.state_root == ZERO_HASH:
diff --git a/tests/mocking/mock_genesis.nim b/tests/mocking/mock_genesis.nim
index 05f88a7db..503d9cb4e 100644
--- a/tests/mocking/mock_genesis.nim
+++ b/tests/mocking/mock_genesis.nim
@@ -17,18 +17,14 @@ import
   ./mock_deposits
 
 proc initGenesisState*(
-    num_validators: uint64 = 8'u64 * SLOTS_PER_EPOCH,
-    beaconStateFork: BeaconStateFork = forkPhase0): ref ForkedHashedBeaconState =
+    num_validators = 8'u64 * SLOTS_PER_EPOCH,
+    cfg = defaultRuntimeConfig): ref ForkedHashedBeaconState =
   let deposits = mockGenesisBalancedDeposits(
       validatorCount = num_validators,
       amountInEth = 32, # We create canonical validators with 32 Eth
       flags = {}
     )
 
-  var cfg = defaultRuntimeConfig
-  if beaconStateFork >= forkAltair:
-    cfg.ALTAIR_FORK_EPOCH = GENESIS_EPOCH
-
   result = (ref ForkedHashedBeaconState)(
     beaconStateFork: forkPhase0,
     hbsPhase0: initialize_hashed_beacon_state_from_eth1(
@@ -36,8 +32,6 @@ proc initGenesisState*(
 
   maybeUpgradeStateToAltair(cfg, result[])
 
-  doAssert result.beaconStateFork == beaconStateFork
-
 when isMainModule:
   # Smoke test
   let state = initGenesisState(num_validators = SLOTS_PER_EPOCH)
diff --git a/tests/testblockutil.nim b/tests/testblockutil.nim
index b67846a31..beb4f263b 100644
--- a/tests/testblockutil.nim
+++ b/tests/testblockutil.nim
@@ -36,7 +36,7 @@ func hackPrivKey*(v: Validator): ValidatorPrivKey =
   let i = int(uint64.fromBytesLE(bytes))
   makeFakeValidatorPrivKey(i)
 
-func makeDeposit*(i: int, flags: UpdateFlags = {}): DepositData =
+func makeDeposit*(i: int, flags: UpdateFlags = {}, cfg = defaultRuntimeConfig): DepositData =
   ## 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 :)
@@ -51,13 +51,12 @@ func makeDeposit*(i: int, flags: UpdateFlags = {}): DepositData =
     amount: MAX_EFFECTIVE_BALANCE)
 
   if skipBLSValidation notin flags:
-    result.signature = get_deposit_signature(
-      defaultRuntimeConfig, result, privkey).toValidatorSig()
+    result.signature = get_deposit_signature(cfg, result, privkey).toValidatorSig()
 
 func makeInitialDeposits*(
-    n = SLOTS_PER_EPOCH, flags: UpdateFlags = {}): seq[DepositData] =
+    n = SLOTS_PER_EPOCH, flags: UpdateFlags = {}, cfg = defaultRuntimeConfig): seq[DepositData] =
   for i in 0..<n.int:
-    result.add makeDeposit(i, flags)
+    result.add makeDeposit(i, flags, cfg = cfg)
 
 func signBlock(
     fork: Fork, genesis_validators_root: Eth2Digest, forked: ForkedBeaconBlock,
@@ -82,13 +81,13 @@ proc addTestBlock*(
     deposits = newSeq[Deposit](),
     graffiti = default(GraffitiBytes),
     flags: set[UpdateFlag] = {},
-    nextSlot = true): ForkedSignedBeaconBlock =
+    nextSlot = true,
+    cfg = defaultRuntimeConfig): ForkedSignedBeaconBlock =
   # Create and add a block to state - state will advance by one slot!
   if nextSlot:
     var rewards: RewardInfo
     doAssert process_slots(
-      defaultRuntimeConfig, state, getStateField(state, slot) + 1, cache,
-      rewards, flags)
+      cfg, state, getStateField(state, slot) + 1, cache, rewards, flags)
 
   let
     proposer_index = get_beacon_proposer_index(
@@ -107,7 +106,7 @@ proc addTestBlock*(
     case state.beaconStateFork
     of forkPhase0:
       let res = makeBeaconBlock(
-        defaultRuntimeConfig,
+        cfg,
         state.hbsPhase0,
         proposer_index.get(),
         parent_root,
@@ -130,7 +129,7 @@ proc addTestBlock*(
       ForkedBeaconBlock.init(res.get())
     of forkAltair:
       let res = makeBeaconBlock(
-        defaultRuntimeConfig,
+        cfg,
         state.hbsAltair,
         proposer_index.get(),
         parent_root,
@@ -169,7 +168,8 @@ proc makeTestBlock*(
     eth1_data = Eth1Data(),
     attestations = newSeq[Attestation](),
     deposits = newSeq[Deposit](),
-    graffiti = default(GraffitiBytes)): ForkedSignedBeaconBlock =
+    graffiti = default(GraffitiBytes),
+    cfg = defaultRuntimeConfig): ForkedSignedBeaconBlock =
   # 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,
@@ -177,7 +177,7 @@ proc makeTestBlock*(
   var tmpState = assignClone(state)
   addTestBlock(
     tmpState[], parent_root, cache, eth1_data, attestations, deposits,
-    graffiti)
+    graffiti, cfg = cfg)
 
 func makeAttestationData*(
     state: ForkedHashedBeaconState, slot: Slot, committee_index: CommitteeIndex,
@@ -315,7 +315,8 @@ iterator makeTestBlocks*(
   parent_root: Eth2Digest,
   cache: var StateCache,
   blocks: int,
-  attested: bool): ForkedSignedBeaconBlock =
+  attested: bool,
+  cfg = defaultRuntimeConfig): ForkedSignedBeaconBlock =
   var
     state = assignClone(state)[]
     parent_root = parent_root
@@ -326,7 +327,7 @@ iterator makeTestBlocks*(
       @[]
 
     let blck = addTestBlock(
-      state, parent_root, cache, attestations = attestations)
+      state, parent_root, cache, attestations = attestations, cfg = cfg)
     yield blck
     parent_root = blck.root