Add function to report highest estimate target tracked per horizon

src/policy/fees.cpp

@@ -684,7 +684,7 @@ CFeeRate CBlockPolicyEstimator::estimateRawFee(int confTarget, double successThr
         break;
     }
     default: {
-        return CFeeRate(0);
+        throw std::out_of_range("CBlockPoicyEstimator::estimateRawFee unknown FeeEstimateHorizon");
     }
     }
 
@@ -703,6 +703,24 @@ CFeeRate CBlockPolicyEstimator::estimateRawFee(int confTarget, double successThr
     return CFeeRate(median);
 }
 
+unsigned int CBlockPolicyEstimator::HighestTargetTracked(FeeEstimateHorizon horizon) const
+{
+    switch (horizon) {
+    case FeeEstimateHorizon::SHORT_HALFLIFE: {
+        return shortStats->GetMaxConfirms();
+    }
+    case FeeEstimateHorizon::MED_HALFLIFE: {
+        return feeStats->GetMaxConfirms();
+    }
+    case FeeEstimateHorizon::LONG_HALFLIFE: {
+        return longStats->GetMaxConfirms();
+    }
+    default: {
+        throw std::out_of_range("CBlockPoicyEstimator::HighestTargetTracked unknown FeeEstimateHorizon");
+    }
+    }
+}
+
 unsigned int CBlockPolicyEstimator::BlockSpan() const
 {
     if (firstRecordedHeight == 0) return 0;

src/policy/fees.h

@@ -216,6 +216,9 @@ class CBlockPolicyEstimator
     /** Empty mempool transactions on shutdown to record failure to confirm for txs still in mempool */
     void FlushUnconfirmed(CTxMemPool& pool);
 
+    /** Calculation of highest target that estimates are tracked for */
+    unsigned int HighestTargetTracked(FeeEstimateHorizon horizon) const;
+
 private:
     unsigned int nBestSeenHeight;
     unsigned int firstRecordedHeight;