diff --git a/src/avalanche/test/processor_tests.cpp b/src/avalanche/test/processor_tests.cpp
--- a/src/avalanche/test/processor_tests.cpp
+++ b/src/avalanche/test/processor_tests.cpp
@@ -32,6 +32,7 @@
     static uint64_t getRound(const AvalancheProcessor &p) { return p.round; }
 };
 
+namespace {
 struct CConnmanTest : public CConnman {
     using CConnman::CConnman;
     void AddNode(CNode &node) {
@@ -46,6 +47,7 @@
         vNodes.clear();
     }
 };
+} // namespace
 
 BOOST_FIXTURE_TEST_SUITE(processor_tests, TestChain100Setup)
 
diff --git a/src/net.h b/src/net.h
--- a/src/net.h
+++ b/src/net.h
@@ -130,6 +130,10 @@
     std::string command;
 };
 
+namespace {
+struct CConnmanTest;
+}
+
 class NetEventsInterface;
 class CConnman {
 public:
@@ -498,7 +502,7 @@
 
     std::atomic<int64_t> m_next_send_inv_to_incoming{0};
 
-    friend struct CConnmanTest;
+    friend struct ::CConnmanTest;
 };
 
 void Discover();
diff --git a/src/test/denialofservice_tests.cpp b/src/test/denialofservice_tests.cpp
--- a/src/test/denialofservice_tests.cpp
+++ b/src/test/denialofservice_tests.cpp
@@ -24,6 +24,7 @@
 
 #include <cstdint>
 
+namespace {
 struct CConnmanTest : public CConnman {
     using CConnman::CConnman;
     void AddNode(CNode &node) {
@@ -38,6 +39,7 @@
         vNodes.clear();
     }
 };
+} // namespace
 
 // Tests these internal-to-net_processing.cpp methods:
 extern bool AddOrphanTx(const CTransactionRef &tx, NodeId peer);