diff --git a/build.nims b/build.nims
index 741484a6..037ecd09 100644
--- a/build.nims
+++ b/build.nims
@@ -25,13 +25,13 @@ task codex, "build codex binary":
   buildBinary "codex", params = "-d:chronicles_runtime_filtering -d:chronicles_log_level=TRACE"
 
 task testCodex, "Build & run Codex tests":
-  test "testCodex", params = "-d:codex_enable_proof_failures=true"
+  test "testCodex", params = "-d:codex_testing=true"
 
 task testContracts, "Build & run Codex Contract tests":
   test "testContracts"
 
 task testIntegration, "Run integration tests":
-  buildBinary "codex", params = "-d:chronicles_runtime_filtering -d:chronicles_log_level=TRACE -d:codex_enable_proof_failures=true"
+  buildBinary "codex", params = "-d:chronicles_runtime_filtering -d:chronicles_log_level=TRACE -d:codex_testing=true"
   test "testIntegration"
 
 task build, "build codex binary":
diff --git a/codex/codex.nim b/codex/codex.nim
index 4fc0f922..31ff6053 100644
--- a/codex/codex.nim
+++ b/codex/codex.nim
@@ -118,7 +118,7 @@ proc bootstrapInteractions(
   if config.persistence:
     # This is used for simulation purposes. Normal nodes won't be compiled with this flag
     # and hence the proof failure will always be 0.
-    when codex_enable_proof_failures:
+    when codex_testing:
       let proofFailures = config.simulateProofFailures
       if proofFailures > 0:
         warn "Enabling proof failure simulation!"
diff --git a/codex/conf.nim b/codex/conf.nim
index 9dc3cb8d..019f0c41 100644
--- a/codex/conf.nim
+++ b/codex/conf.nim
@@ -44,7 +44,7 @@ export net, DefaultQuotaBytes, DefaultBlockTtl, DefaultBlockMaintenanceInterval,
 
 const
   codex_enable_api_debug_peers* {.booldefine.} = false
-  codex_enable_proof_failures* {.booldefine.} = false
+  codex_testing* {.booldefine.} = false
   codex_enable_log_counter* {.booldefine.} = false
 
 type
diff --git a/codex/contracts/clock.nim b/codex/contracts/clock.nim
index 2c6a1728..af076ee0 100644
--- a/codex/contracts/clock.nim
+++ b/codex/contracts/clock.nim
@@ -2,6 +2,7 @@ import pkg/ethers
 import pkg/chronos
 import pkg/stint
 import ../clock
+import ../conf
 
 export clock
 
@@ -41,14 +42,17 @@ method stop*(clock: OnChainClock) {.async.} =
   await clock.subscription.unsubscribe()
 
 method now*(clock: OnChainClock): SecondsSince1970 =
-  try:
-    if queriedBlock =? (waitFor clock.provider.getBlock(BlockTag.latest)):
-      if queriedBlock.timestamp != clock.lastBlockTime:
-        trace "queried block and event block are not in sync",
-          queriedBlockLessThanEventBlock = queriedBlock.timestamp < clock.lastBlockTime
-      return queriedBlock.timestamp.truncate(int64)
-  except CatchableError as e:
-    warn "failed to get latest block timestamp"
+  when codex_testing:
+    # hardhat's latest block.timestamp is usually 1s behind the block timestamp
+    # in the newHeads event. When testing, always return the latest block.
+    try:
+      if queriedBlock =? (waitFor clock.provider.getBlock(BlockTag.latest)):
+        return queriedBlock.timestamp.truncate(int64)
+    except CatchableError as e:
+      warn "failed to get latest block timestamp"
+      return clock.lastBlockTime.truncate(int64)
+
+  else:
     return clock.lastBlockTime.truncate(int64)
 
 method waitUntil*(clock: OnChainClock, time: SecondsSince1970) {.async.} =
diff --git a/codex/sales/states/filled.nim b/codex/sales/states/filled.nim
index c5bc4c27..4fe551fd 100644
--- a/codex/sales/states/filled.nim
+++ b/codex/sales/states/filled.nim
@@ -51,7 +51,7 @@ method run*(state: SaleFilled, machine: Machine): Future[?State] {.async.} =
     if err =? (await onExpiryUpdate(request.content.cid, requestEnd)).errorOption:
       return some State(SaleErrored(error: err))
 
-    when codex_enable_proof_failures:
+    when codex_testing:
       if context.simulateProofFailures > 0:
         info "Proving with failure rate", rate = context.simulateProofFailures
         return some State(SaleProvingSimulated(failEveryNProofs: context.simulateProofFailures))
diff --git a/codex/sales/states/provingsimulated.nim b/codex/sales/states/provingsimulated.nim
index f5753cf2..b0ae7206 100644
--- a/codex/sales/states/provingsimulated.nim
+++ b/codex/sales/states/provingsimulated.nim
@@ -1,5 +1,5 @@
 import ../../conf
-when codex_enable_proof_failures:
+when codex_testing:
   import std/strutils
   import pkg/chronicles
   import pkg/stint
diff --git a/codex/validation.nim b/codex/validation.nim
index 2be39975..b7557f93 100644
--- a/codex/validation.nim
+++ b/codex/validation.nim
@@ -4,6 +4,7 @@ import pkg/chronos
 import pkg/chronicles
 import ./market
 import ./clock
+import ./utils/exceptions
 
 export market
 export sets
@@ -78,7 +79,7 @@ proc markProofAsMissing(validation: Validation,
   except CancelledError:
     raise
   except CatchableError as e:
-    error "Marking proof as missing failed", msg = e.msg
+    error "Marking proof as missing failed", msg = e.msgDetail
 
 proc markProofsAsMissing(validation: Validation) {.async.} =
   for slotId in validation.slots:
diff --git a/config.nims b/config.nims
index 031cdaa7..3acc58b5 100644
--- a/config.nims
+++ b/config.nims
@@ -95,7 +95,7 @@ if not defined(macosx):
     --define:nimStackTraceOverride
     switch("import", "libbacktrace")
 
-switch("define", "codex_enable_proof_failures=true")
+switch("define", "codex_testing=true")
 
 # `switch("warning[CaseTransition]", "off")` fails with "Error: invalid command line option: '--warning[CaseTransition]'"
 switch("warning", "CaseTransition:off")