diff --git a/electrum/commands.py b/electrum/commands.py
index de5398d38..ff925d68d 100644
--- a/electrum/commands.py
+++ b/electrum/commands.py
@@ -71,7 +71,7 @@ from .lnutil import channel_id_from_funding_tx, LnFeatures, SENT, MIN_FINAL_CLTV
 from .plugin import run_hook, DeviceMgr, Plugins
 from .version import ELECTRUM_VERSION
 from .simple_config import SimpleConfig
-from .fee_policy import FeePolicy
+from .fee_policy import FeePolicy, FEE_ETA_TARGETS, FEERATE_DEFAULT_RELAY
 from . import GuiImportError
 from . import crypto
 from . import constants
@@ -1576,6 +1576,27 @@ class Commands(Logger):
             'tooltip': tooltip,
         }
 
+    @command('n')
+    async def test_inject_fee_etas(self, fee_est):
+        """
+        Inject fee estimates into the network object, as if they were coming from connected servers.
+        Useful on regtest.
+
+        arg:str:fee_est:dict of ETA-based fee estimates, encoded as str
+        """
+        if not isinstance(fee_est, dict):
+            fee_est = ast.literal_eval(fee_est)
+        assert isinstance(fee_est, dict), f"unexpected type for fee_est. got {repr(fee_est)}"
+        # populate missing high-block-number estimates using default relay fee.
+        # e.g. {"25": 2222} -> {"25": 2222, "144": 1000, "1008": 1000}
+        furthest_estimate = max(fee_est.keys()) if fee_est else 0
+        further_fee_est = {
+            eta_target: FEERATE_DEFAULT_RELAY for eta_target in FEE_ETA_TARGETS
+            if eta_target > furthest_estimate
+        }
+        fee_est.update(further_fee_est)
+        self.network.update_fee_estimates(fee_est=fee_est)
+
     @command('w')
     async def removelocaltx(self, txid, wallet: Abstract_Wallet = None):
         """Remove a 'local' transaction from the wallet, and its dependent
diff --git a/electrum/fee_policy.py b/electrum/fee_policy.py
index 958c35854..33b7eb384 100644
--- a/electrum/fee_policy.py
+++ b/electrum/fee_policy.py
@@ -375,8 +375,9 @@ class FeeTimeEstimates:
               just try to do the estimate and handle a potential None result. That way,
               estimation works for targets we have, even if some targets are missing.
         """
-        # we do not request estimate for next block fee, hence -1
-        return len(self.data) == len(FEE_ETA_TARGETS) - 1
+        targets = set(FEE_ETA_TARGETS)
+        targets.discard(1)  # rm "next block" target
+        return all(target in self.data for target in targets)
 
     def set_data(self, nblock_target: int, fee_per_kb: int):
         assert isinstance(nblock_target, int), f"expected int, got {nblock_target!r}"