Merge #20477: net: Add unit testing of node eviction logic

fee88237e0 Assert eviction at >= 29 candidates. Assert non-eviction at <= 20 candidates. (practicalswift)
685c428de0 test: Add unit testing of node eviction logic (practicalswift)
ed73f8cee0 net: Move eviction node selection logic to SelectNodeToEvict(...) (practicalswift)

Pull request description:

  Add unit testing of node eviction logic.

  Closes #19966.

ACKs for top commit:
  jonatack:
    ACK fee88237e0
  MarcoFalke:
    ACK fee88237e0 🐼

Tree-SHA512: 0827c35609122ca42bfabb17feaaee35c191ab4dc2e428282af425a6c176eaeaff2789b74a4f7eb4ca6b8cb10603068e90ca800e6ef3bc3904d50e76616f7a2b

src/net.h

@@ -33,6 +33,7 @@
 #include <map>
 #include <memory>
 #include <thread>
+#include <vector>
 
 class CScheduler;
 class CNode;
@@ -1239,4 +1240,21 @@ inline std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now,
     return std::chrono::microseconds{PoissonNextSend(now.count(), average_interval.count())};
 }
 
+struct NodeEvictionCandidate
+{
+    NodeId id;
+    int64_t nTimeConnected;
+    int64_t nMinPingUsecTime;
+    int64_t nLastBlockTime;
+    int64_t nLastTXTime;
+    bool fRelevantServices;
+    bool fRelayTxes;
+    bool fBloomFilter;
+    uint64_t nKeyedNetGroup;
+    bool prefer_evict;
+    bool m_is_local;
+};
+
+[[nodiscard]] Optional<NodeId> SelectNodeToEvict(std::vector<NodeEvictionCandidate>&& vEvictionCandidates);
+
 #endif // BITCOIN_NET_H