[init] Create deterministic addrman in tests using -test=addrman

Supposing there are 2 different addresses to be placed in an addrman
table. During every test run, a different [bucket,position] would be
calculated for each address. These calculated [bucket,position] could
end up being the same for the 2 different addresses in some test runs
and result in collisions in the addrman. We wouldn't be able to
predict when the collisions are going to happen because we can't
predict the nKey value which is chosen at random. This can cause
flaky tests.

Improve this by allowing deterministic addrman creation in the
functional tests. This creates an addrman with fixed `nKey` = 1 and
we can know the [bucket,position] collisions beforehand, safely add
more addresses in an addrman table and write more extensive tests.

src/addrdb.cpp

@@ -185,7 +185,9 @@ void ReadFromStream(AddrMan& addr, DataStream& ssPeers)
 util::Result<std::unique_ptr<AddrMan>> LoadAddrman(const NetGroupManager& netgroupman, const ArgsManager& args)
 {
     auto check_addrman = std::clamp<int32_t>(args.GetIntArg("-checkaddrman", DEFAULT_ADDRMAN_CONSISTENCY_CHECKS), 0, 1000000);
-    auto addrman{std::make_unique<AddrMan>(netgroupman, /*deterministic=*/false, /*consistency_check_ratio=*/check_addrman)};
+    bool deterministic = HasTestOption(args, "addrman"); // use a deterministic addrman only for tests
+
+    auto addrman{std::make_unique<AddrMan>(netgroupman, /*deterministic=*/deterministic, /*consistency_check_ratio=*/check_addrman)};
 
     const auto start{SteadyClock::now()};
     const auto path_addr{args.GetDataDirNet() / "peers.dat"};
@@ -194,15 +196,15 @@ util::Result<std::unique_ptr<AddrMan>> LoadAddrman(const NetGroupManager& netgro
         LogPrintf("Loaded %i addresses from peers.dat  %dms\n", addrman->Size(), Ticks<std::chrono::milliseconds>(SteadyClock::now() - start));
     } catch (const DbNotFoundError&) {
         // Addrman can be in an inconsistent state after failure, reset it
-        addrman = std::make_unique<AddrMan>(netgroupman, /*deterministic=*/false, /*consistency_check_ratio=*/check_addrman);
+        addrman = std::make_unique<AddrMan>(netgroupman, /*deterministic=*/deterministic, /*consistency_check_ratio=*/check_addrman);
         LogPrintf("Creating peers.dat because the file was not found (%s)\n", fs::quoted(fs::PathToString(path_addr)));
         DumpPeerAddresses(args, *addrman);
     } catch (const InvalidAddrManVersionError&) {
         if (!RenameOver(path_addr, (fs::path)path_addr + ".bak")) {
             return util::Error{strprintf(_("Failed to rename invalid peers.dat file. Please move or delete it and try again."))};
         }
         // Addrman can be in an inconsistent state after failure, reset it
-        addrman = std::make_unique<AddrMan>(netgroupman, /*deterministic=*/false, /*consistency_check_ratio=*/check_addrman);
+        addrman = std::make_unique<AddrMan>(netgroupman, /*deterministic=*/deterministic, /*consistency_check_ratio=*/check_addrman);
         LogPrintf("Creating new peers.dat because the file version was not compatible (%s). Original backed up to peers.dat.bak\n", fs::quoted(fs::PathToString(path_addr)));
         DumpPeerAddresses(args, *addrman);
     } catch (const std::exception& e) {

src/common/args.cpp

@@ -683,6 +683,7 @@ std::string HelpMessageOpt(const std::string &option, const std::string &message
 }
 
 const std::vector<std::string> TEST_OPTIONS_DOC{
+    "addrman (use deterministic addrman)",
 };
 
 bool HasTestOption(const ArgsManager& args, const std::string& test_option)