Create net_peer_connection unit tests

for initial partial unit test coverage of these CConnman class methods:

- AddNode()
- ConnectNode()
- GetAddedNodeInfo()
- AlreadyConnectedToAddress()
- ThreadOpenAddedConnections()

and of the GetAddedNodeInfo() call in RPC addnode.

src/Makefile.test.include

@@ -111,6 +111,7 @@ BITCOIN_TESTS =\
   test/miniscript_tests.cpp \
   test/minisketch_tests.cpp \
   test/multisig_tests.cpp \
+  test/net_peer_connection_tests.cpp \
   test/net_peer_eviction_tests.cpp \
   test/net_tests.cpp \
   test/netbase_tests.cpp \

src/test/net_peer_connection_tests.cpp

@@ -0,0 +1,147 @@
+// Copyright (c) 2023-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <chainparams.h>
+#include <compat/compat.h>
+#include <net.h>
+#include <net_processing.h>
+#include <netaddress.h>
+#include <netbase.h>
+#include <netgroup.h>
+#include <node/connection_types.h>
+#include <protocol.h>
+#include <random.h>
+#include <test/util/logging.h>
+#include <test/util/net.h>
+#include <test/util/random.h>
+#include <test/util/setup_common.h>
+#include <tinyformat.h>
+#include <util/chaintype.h>
+#include <version.h>
+
+#include <algorithm>
+#include <cstdint>
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include <boost/test/unit_test.hpp>
+
+struct LogIPsTestingSetup : public TestingSetup {
+    LogIPsTestingSetup()
+        : TestingSetup{ChainType::MAIN, /*extra_args=*/{"-logips"}} {}
+};
+
+BOOST_FIXTURE_TEST_SUITE(net_peer_connection_tests, LogIPsTestingSetup)
+
+static CService ip(uint32_t i)
+{
+    struct in_addr s;
+    s.s_addr = i;
+    return CService{CNetAddr{s}, Params().GetDefaultPort()};
+}
+
+/** Create a peer and connect to it. If the optional `address` (IP/CJDNS only) isn't passed, a random address is created. */
+static void AddPeer(NodeId& id, std::vector<CNode*>& nodes, PeerManager& peerman, ConnmanTestMsg& connman, ConnectionType conn_type, bool onion_peer = false, std::optional<std::string> address = std::nullopt)
+{
+    CAddress addr{};
+
+    if (address.has_value()) {
+        addr = CAddress{MaybeFlipIPv6toCJDNS(LookupNumeric(address.value(), Params().GetDefaultPort())), NODE_NONE};
+    } else if (onion_peer) {
+        auto tor_addr{g_insecure_rand_ctx.randbytes(ADDR_TORV3_SIZE)};
+        BOOST_REQUIRE(addr.SetSpecial(OnionToString(tor_addr)));
+    }
+
+    while (!addr.IsLocal() && !addr.IsRoutable()) {
+        addr = CAddress{ip(g_insecure_rand_ctx.randbits(32)), NODE_NONE};
+    }
+
+    BOOST_REQUIRE(addr.IsValid());
+
+    const bool inbound_onion{onion_peer && conn_type == ConnectionType::INBOUND};
+
+    nodes.emplace_back(new CNode{++id,
+                                 /*sock=*/nullptr,
+                                 addr,
+                                 /*nKeyedNetGroupIn=*/0,
+                                 /*nLocalHostNonceIn=*/0,
+                                 CAddress{},
+                                 /*addrNameIn=*/"",
+                                 conn_type,
+                                 /*inbound_onion=*/inbound_onion});
+    CNode& node = *nodes.back();
+    node.SetCommonVersion(PROTOCOL_VERSION);
+
+    peerman.InitializeNode(node, ServiceFlags(NODE_NETWORK | NODE_WITNESS));
+    node.fSuccessfullyConnected = true;
+
+    connman.AddTestNode(node);
+}
+
+BOOST_AUTO_TEST_CASE(test_addnode_getaddednodeinfo_and_connection_detection)
+{
+    auto connman = std::make_unique<ConnmanTestMsg>(0x1337, 0x1337, *m_node.addrman, *m_node.netgroupman, Params());
+    auto peerman = PeerManager::make(*connman, *m_node.addrman, nullptr, *m_node.chainman, *m_node.mempool, {});
+    NodeId id{0};
+    std::vector<CNode*> nodes;
+
+    // Connect a localhost peer.
+    {
+        ASSERT_DEBUG_LOG("Added connection to 127.0.0.1:8333 peer=1");
+        AddPeer(id, nodes, *peerman, *connman, ConnectionType::MANUAL, /*onion_peer=*/false, /*address=*/"127.0.0.1");
+        BOOST_REQUIRE(nodes.back() != nullptr);
+    }
+
+    // Call ConnectNode(), which is also called by RPC addnode onetry, for a localhost
+    // address that resolves to multiple IPs, including that of the connected peer.
+    // The connection attempt should consistently fail due to the check in ConnectNode().
+    for (int i = 0; i < 10; ++i) {
+        ASSERT_DEBUG_LOG("Not opening a connection to localhost, already connected to 127.0.0.1:8333");
+        BOOST_CHECK(!connman->ConnectNodePublic(*peerman, "localhost", ConnectionType::MANUAL));
+    }
+
+    // Add 3 more peer connections.
+    AddPeer(id, nodes, *peerman, *connman, ConnectionType::OUTBOUND_FULL_RELAY);
+    AddPeer(id, nodes, *peerman, *connman, ConnectionType::BLOCK_RELAY, /*onion_peer=*/true);
+    AddPeer(id, nodes, *peerman, *connman, ConnectionType::INBOUND);
+
+    BOOST_TEST_MESSAGE("Call AddNode() for all the peers");
+    for (auto node : connman->TestNodes()) {
+        BOOST_CHECK(connman->AddNode({/*m_added_node=*/node->addr.ToStringAddrPort(), /*m_use_v2transport=*/true}));
+        BOOST_TEST_MESSAGE(strprintf("peer id=%s addr=%s", node->GetId(), node->addr.ToStringAddrPort()));
+    }
+
+    BOOST_TEST_MESSAGE("\nCall AddNode() with 2 addrs resolving to existing localhost addnode entry; neither should be added");
+    BOOST_CHECK(!connman->AddNode({/*m_added_node=*/"127.0.0.1", /*m_use_v2transport=*/true}));
+    BOOST_CHECK(!connman->AddNode({/*m_added_node=*/"127.1", /*m_use_v2transport=*/true}));
+
+    BOOST_TEST_MESSAGE("\nExpect GetAddedNodeInfo to return expected number of peers with `include_connected` true/false");
+    BOOST_CHECK_EQUAL(connman->GetAddedNodeInfo(/*include_connected=*/true).size(), nodes.size());
+    BOOST_CHECK(connman->GetAddedNodeInfo(/*include_connected=*/false).empty());
+
+    BOOST_TEST_MESSAGE("\nPrint GetAddedNodeInfo contents:");
+    for (const auto& info : connman->GetAddedNodeInfo(/*include_connected=*/true)) {
+        BOOST_TEST_MESSAGE(strprintf("\nadded node: %s", info.m_params.m_added_node));
+        BOOST_TEST_MESSAGE(strprintf("connected: %s", info.fConnected));
+        if (info.fConnected) {
+            BOOST_TEST_MESSAGE(strprintf("IP address: %s", info.resolvedAddress.ToStringAddrPort()));
+            BOOST_TEST_MESSAGE(strprintf("direction: %s", info.fInbound ? "inbound" : "outbound"));
+        }
+    }
+
+    BOOST_TEST_MESSAGE("\nCheck that all connected peers are correctly detected as connected");
+    for (auto node : connman->TestNodes()) {
+        BOOST_CHECK(connman->AlreadyConnectedPublic(node->addr));
+    }
+
+    // Clean up
+    for (auto node : connman->TestNodes()) {
+        peerman->FinalizeNode(*node);
+    }
+    connman->ClearTestNodes();
+}
+
+BOOST_AUTO_TEST_SUITE_END()