diff --git a/src/xrpld/app/main/Application.cpp b/src/xrpld/app/main/Application.cpp
index 8f59c19f01..036a209af4 100644
--- a/src/xrpld/app/main/Application.cpp
+++ b/src/xrpld/app/main/Application.cpp
@@ -61,6 +61,7 @@
 #include <xrpld/shamap/NodeFamily.h>
 #include <xrpl/basics/ByteUtilities.h>
 #include <xrpl/basics/contract.h>
+#include <xrpl/basics/random.h>
 #include <xrpl/basics/FileUtilities.h>
 #include <xrpl/basics/ResolverAsio.h>
 #include <xrpl/basics/random.h>
@@ -80,6 +81,7 @@
 #include <boost/system/error_code.hpp>
 
 #include <date/date.h>
+#include <functional>
 
 #include <chrono>
 #include <condition_variable>
@@ -172,6 +174,9 @@ public:
     OverlayFactory overlayFactory_;
     TimeoutCounterTimerFactory peerTimerFactory_;
     TimeoutCounterTimerFactory timeoutCounterTimerFactory_;
+    Stopwatch& stopwatch_;
+    Stopwatch& preciseStopwatch_;
+    std::function<beast::xor_shift_engine&()> prng_;
 
     std::unique_ptr<DatagramMonitor> datagram_monitor_;
 
@@ -282,9 +287,8 @@ public:
         std::unique_ptr<Logs> logs,
         std::unique_ptr<TimeKeeper> timeKeeper,
         OverlayFactory overlayFactory,
-        [[maybe_unused]] beast::abstract_clock<std::chrono::steady_clock>*
-            injectedClock,
-        [[maybe_unused]] beast::xor_shift_engine* injectedPrng,
+        beast::abstract_clock<std::chrono::steady_clock>* injectedClock,
+        beast::xor_shift_engine* injectedPrng,
         TimeoutCounterTimerFactory timeoutCounterTimerFactory,
         TimeoutCounterTimerFactory peerTimerFactory)
         : BasicApp(numberOfThreads(*config))
@@ -310,6 +314,16 @@ public:
                   return makeAsioTimeoutCounterTimer(getIOService());
               };
           }())
+        , stopwatch_(injectedClock ? *injectedClock : stopwatch())
+        , preciseStopwatch_(
+              injectedClock
+                  ? *injectedClock
+                  : beast::get_abstract_clock<std::chrono::steady_clock>())
+        , prng_([injectedPrng]() -> beast::xor_shift_engine& {
+              if (injectedPrng)
+                  return *injectedPrng;
+              return default_prng();
+          })
         , instanceCookie_(
               1 +
               rand_int(
@@ -374,14 +388,14 @@ public:
               "NodeCache",
               16384,
               std::chrono::seconds{90},
-              stopwatch(),
+              stopwatch_,
               logs_->journal("TaggedCache"))
 
         , cachedSLEs_(
               "Cached SLEs",
               0,
               std::chrono::minutes(1),
-              stopwatch(),
+              stopwatch_,
               logs_->journal("CachedSLEs"))
 
         , validatorKeys_(*config_, m_journal)
@@ -404,7 +418,7 @@ public:
 
         , m_ledgerMaster(std::make_unique<LedgerMaster>(
               *this,
-              stopwatch(),
+              stopwatch_,
               m_collectorManager->collector(),
               logs_->journal("LedgerMaster")))
 
@@ -416,7 +430,7 @@ public:
         //
         , m_inboundLedgers(make_InboundLedgers(
               *this,
-              stopwatch(),
+              stopwatch_,
               m_collectorManager->collector()))
 
         , m_inboundTransactions(make_InboundTransactions(
@@ -435,12 +449,12 @@ public:
               "AcceptedLedger",
               4,
               std::chrono::minutes{1},
-              stopwatch(),
+              stopwatch_,
               logs_->journal("TaggedCache"))
 
         , m_networkOPs(make_NetworkOPs(
               *this,
-              stopwatch(),
+              preciseStopwatch_,
               config_->standalone(),
               config_->NETWORK_QUORUM,
               config_->START_VALID,
@@ -484,12 +498,12 @@ public:
               std::make_unique<LoadFeeTrack>(logs_->journal("LoadManager")))
 
         , hashRouter_(std::make_unique<HashRouter>(
-              stopwatch(),
+              stopwatch_,
               HashRouter::getDefaultHoldTime()))
 
         , mValidations(
               ValidationParms(),
-              stopwatch(),
+              stopwatch_,
               *this,
               logs_->journal("Validations"))
 
@@ -656,6 +670,24 @@ public:
         return peerTimerFactory_();
     }
 
+    Stopwatch&
+    getStopwatch() override
+    {
+        return stopwatch_;
+    }
+
+    Stopwatch&
+    getPreciseStopwatch() override
+    {
+        return preciseStopwatch_;
+    }
+
+    beast::xor_shift_engine&
+    getPrng() override
+    {
+        return prng_();
+    }
+
     std::chrono::milliseconds
     getIOLatency() override
     {
@@ -2183,7 +2215,7 @@ ApplicationImp::loadOldLedger(
                         hash,
                         0,
                         InboundLedger::Reason::GENERIC,
-                        stopwatch(),
+                        stopwatch_,
                         make_DummyPeerSet(*this));
                     if (il->checkLocal())
                         loadLedger = il->getLedger();
@@ -2227,7 +2259,7 @@ ApplicationImp::loadOldLedger(
                     replayLedger->info().parentHash,
                     0,
                     InboundLedger::Reason::GENERIC,
-                    stopwatch(),
+                    stopwatch_,
                     make_DummyPeerSet(*this));
 
                 if (il->checkLocal())
diff --git a/src/xrpld/app/misc/NetworkOPs.cpp b/src/xrpld/app/misc/NetworkOPs.cpp
index a7cd90458a..b2a61ff199 100644
--- a/src/xrpld/app/misc/NetworkOPs.cpp
+++ b/src/xrpld/app/misc/NetworkOPs.cpp
@@ -183,7 +183,7 @@ public:
               ledgerMaster,
               *m_localTX,
               app.getInboundTransactions(),
-              beast::get_abstract_clock<std::chrono::steady_clock>(),
+              clock,
               validatorKeys,
               app_.logs().journal("LedgerConsensus"))
         , m_ledgerMaster(ledgerMaster)
@@ -335,6 +335,9 @@ public:
     void
     setStateTimer() override;
 
+    void
+    heartbeatTick() override;
+
     void
     setNeedNetworkLedger() override;
     void
@@ -907,6 +910,9 @@ NetworkOPsImp::setTimer(
 void
 NetworkOPsImp::setHeartbeatTimer()
 {
+    if (app_.config().manualHeartbeat)
+        return;
+
     setTimer(
         heartbeatTimer_,
         mConsensus.parms().ledgerGRANULARITY,
@@ -918,6 +924,14 @@ NetworkOPsImp::setHeartbeatTimer()
         [this]() { setHeartbeatTimer(); });
 }
 
+void
+NetworkOPsImp::heartbeatTick()
+{
+    m_job_queue.addJob(jtNETOP_TIMER, "NetOPs.heartbeat", [this]() {
+        processHeartbeatTimer();
+    });
+}
+
 void
 NetworkOPsImp::setClusterTimer()
 {
diff --git a/src/xrpld/app/misc/NetworkOPs.h b/src/xrpld/app/misc/NetworkOPs.h
index aafef2585a..69fd30e722 100644
--- a/src/xrpld/app/misc/NetworkOPs.h
+++ b/src/xrpld/app/misc/NetworkOPs.h
@@ -163,6 +163,11 @@ public:
     virtual void
     setStateTimer() = 0;
 
+    /** Posts the same heartbeat job the asio timer would. Used when
+        Config::manualHeartbeat suppresses the wall-clock timer. */
+    virtual void
+    heartbeatTick() = 0;
+
     virtual void
     setNeedNetworkLedger() = 0;
     virtual void