From 43b09b993d0a5a8178d70a0149a5301aed82bb8d Mon Sep 17 00:00:00 2001
From: Chandra Pratap <chandrapratap3519@gmail.com>
Date: Thu, 11 Dec 2025 10:28:06 +0000
Subject: [PATCH] fuzz: Improve oracle for existing CCoinControl tests

---
 src/wallet/test/fuzz/coincontrol.cpp | 34 +++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/src/wallet/test/fuzz/coincontrol.cpp b/src/wallet/test/fuzz/coincontrol.cpp
index 6774a21d01b..e46a469f9ea 100644
--- a/src/wallet/test/fuzz/coincontrol.cpp
+++ b/src/wallet/test/fuzz/coincontrol.cpp
@@ -57,26 +57,48 @@ FUZZ_TARGET(coincontrol, .init = initialize_coincontrol)
             },
             [&] {
                 (void)coin_control.Select(out_point);
+                assert(coin_control.IsSelected(out_point));
             },
             [&] {
                 const CTxOut tx_out{ConsumeMoney(fuzzed_data_provider), ConsumeScript(fuzzed_data_provider)};
-                (void)coin_control.Select(out_point).SetTxOut(tx_out);
+                auto& input = coin_control.Select(out_point);
+                const auto set_tx_out{fuzzed_data_provider.ConsumeBool()};
+                if (set_tx_out) {
+                    input.SetTxOut(tx_out);
+                }
+                auto has_tx_out{input.HasTxOut()};
+                auto is_external_selected{coin_control.IsExternalSelected(out_point)};
+                if (set_tx_out) {
+                    assert(has_tx_out);
+                    assert(input.GetTxOut() == tx_out);
+                    assert(is_external_selected);
+                } else if (!has_tx_out) {
+                    assert(!is_external_selected);
+                }
             },
             [&] {
-                (void)coin_control.UnSelect(out_point);
+                coin_control.UnSelect(out_point);
+                assert(!coin_control.IsSelected(out_point));
             },
             [&] {
-                (void)coin_control.UnSelectAll();
+                coin_control.UnSelectAll();
+                assert(!coin_control.HasSelected());
             },
             [&] {
-                (void)coin_control.ListSelected();
+                const std::vector<COutPoint> selected = coin_control.ListSelected();
+                for (const auto& out : selected) {
+                    assert(coin_control.IsSelected(out));
+                }
             },
             [&] {
                 int64_t weight{fuzzed_data_provider.ConsumeIntegral<int64_t>()};
-                (void)coin_control.SetInputWeight(out_point, weight);
+                coin_control.SetInputWeight(out_point, weight);
+                assert(coin_control.GetInputWeight(out_point) == weight);
             },
             [&] {
-                (void)coin_control.GetInputWeight(out_point);
+                const bool is_selected = coin_control.IsSelected(out_point);
+                assert(!coin_control.GetInputWeight(out_point) || is_selected);
+                assert(!coin_control.GetSequence(out_point) || is_selected);
             });
     }
 }