From 475057abda233d7599cb1cbc375b4788402f0098 Mon Sep 17 00:00:00 2001
From: Thomas Eizinger <thomas@eizinger.io>
Date: Thu, 12 Aug 2021 18:12:40 +1000
Subject: [PATCH] Add proptest for max_giveable and signing PSBT

---
 swap/proptest-regressions/bitcoin/wallet.txt |  7 +++++++
 swap/src/bitcoin/wallet.rs                   | 17 +++++++++++++++++
 swap/src/proptest.rs                         | 12 ++++++++++++
 3 files changed, 36 insertions(+)
 create mode 100644 swap/proptest-regressions/bitcoin/wallet.txt

diff --git a/swap/proptest-regressions/bitcoin/wallet.txt b/swap/proptest-regressions/bitcoin/wallet.txt
new file mode 100644
index 00000000..843cefb4
--- /dev/null
+++ b/swap/proptest-regressions/bitcoin/wallet.txt
@@ -0,0 +1,7 @@
+# Seeds for failure cases proptest has generated in the past. It is
+# automatically read and these particular cases re-run before any
+# novel cases are generated.
+#
+# It is recommended to check this file in to source control so that
+# everyone who runs the test benefits from these saved cases.
+cc 849f8b01f49fc9a913100203698a9151d8de8a37564e1d3b1e3b4169e192f58a # shrinks to funding_amount = 290250686, num_utxos = 3, sats_per_vb = 75.35638, key = ExtendedPrivKey { network: Regtest, depth: 0, parent_fingerprint: 00000000, child_number: Normal { index: 0 }, private_key: [private key data], chain_code: 0b7a29ca6990bbc9b9187c1d1a07e2cf68e32f5ce55d2df01edf8a4ac2ee2a4b }, alice = Point<Normal,Public,NonZero>(0299a8c6a662e2e9e8ee7c6889b75a51c432812b4bf70c1d76eace63abc1bdfb1b), bob = Point<Normal,Public,NonZero>(027165b1f9924030c90d38c511da0f4397766078687997ed34d6ef2743d2a7bbed)
diff --git a/swap/src/bitcoin/wallet.rs b/swap/src/bitcoin/wallet.rs
index b544e650..82be3dc6 100644
--- a/swap/src/bitcoin/wallet.rs
+++ b/swap/src/bitcoin/wallet.rs
@@ -1201,4 +1201,21 @@ DEBUG swap::bitcoin::wallet: Bitcoin transaction status changed txid=00000000000
     fn confs(confirmations: u32) -> ScriptStatus {
         ScriptStatus::from_confirmations(confirmations)
     }
+
+    proptest::proptest! {
+        #[test]
+        fn funding_never_fails_with_insufficient_funds(funding_amount in 3000u32.., num_utxos in 1..5u8, sats_per_vb in 1.0..500.0f32, key in crate::proptest::bitcoin::extended_priv_key(), alice in crate::proptest::ecdsa_fun::point(), bob in crate::proptest::ecdsa_fun::point()) {
+            proptest::prop_assume!(alice != bob);
+
+            tokio::runtime::Runtime::new().unwrap().block_on(async move {
+                let wallet = WalletBuilder::new(funding_amount as u64).with_key(key).with_num_utxos(num_utxos).with_fees(sats_per_vb, 1000).build();
+
+                let amount = wallet.max_giveable(TxLock::script_size()).await.unwrap();
+                let psbt: PartiallySignedTransaction = TxLock::new(&wallet, amount, PublicKey::from(alice), PublicKey::from(bob), wallet.new_address().await.unwrap()).await.unwrap().into();
+                let result = wallet.sign_and_finalize(psbt).await;
+
+                result.expect("transaction to be signed");
+            });
+        }
+    }
 }
diff --git a/swap/src/proptest.rs b/swap/src/proptest.rs
index 0c7ee7b3..41b28785 100644
--- a/swap/src/proptest.rs
+++ b/swap/src/proptest.rs
@@ -15,3 +15,15 @@ pub mod ecdsa_fun {
         })
     }
 }
+
+pub mod bitcoin {
+    use super::*;
+    use ::bitcoin::util::bip32::ExtendedPrivKey;
+    use ::bitcoin::Network;
+
+    pub fn extended_priv_key() -> impl Strategy<Value = ExtendedPrivKey> {
+        prop::array::uniform8(0..255u8).prop_filter_map("invalid secret key generated", |bytes| {
+            ExtendedPrivKey::new_master(Network::Regtest, &bytes).ok()
+        })
+    }
+}