common: impl Arbitrary, proptests on LxInvoice

common/src/ln/invoice.rs

@@ -25,3 +25,102 @@ impl Display for LxInvoice {
 // TODO(max): We should proptest the serde and fromstr/display impls but it's
 // non-trivial to impl Arbitrary for Invoice. lightning_invoice::InvoiceBuilder
 // is probably the way.
+
+// `any::<String>()` requires proptest feature std which doesn't work in SGX
+#[cfg(all(test, not(target_env = "sgx")))]
+mod test {
+    use std::time::{Duration, SystemTime, UNIX_EPOCH};
+
+    use bitcoin::hashes::{sha256, Hash};
+    use bitcoin::secp256k1::{self, Secp256k1};
+    use lightning::ln::PaymentSecret;
+    use lightning_invoice::{Currency, InvoiceBuilder};
+    use proptest::arbitrary::{any, Arbitrary};
+    use proptest::strategy::{BoxedStrategy, Strategy};
+
+    use super::*;
+    use crate::cli::Network;
+    use crate::rng::SmallRng;
+    use crate::root_seed::RootSeed;
+    use crate::test_utils::roundtrip;
+
+    impl Arbitrary for LxInvoice {
+        type Parameters = ();
+        type Strategy = BoxedStrategy<Self>;
+        fn arbitrary_with(_args: Self::Parameters) -> Self::Strategy {
+            let currency = any::<Network>().prop_map(Currency::from);
+            let description = any::<String>();
+
+            let payment_hash = any::<[u8; 32]>()
+                .prop_map(|buf| sha256::Hash::from_slice(&buf).unwrap());
+
+            let payment_secret = any::<[u8; 32]>().prop_map(PaymentSecret);
+
+            let timestamp = any::<SystemTime>().prop_map(|system_time| {
+                // TODO: We convert to and from unix seconds because LDK's
+                // fromstr/display impl fails the roundtrip test if the
+                // SystemTime passed to InvoiceBuilder::timestamp isn't rounded
+                // to the nearest second. We can drop the prop_map once
+                // <https://github.com/lightningdevkit/rust-lightning/pull/1760>
+                // is merged and released.
+                let unix_secs = system_time
+                    .duration_since(UNIX_EPOCH)
+                    .unwrap_or(Duration::from_secs(0))
+                    .as_secs();
+                UNIX_EPOCH + Duration::from_secs(unix_secs)
+            });
+
+            let min_final_cltv_expiry = any::<u64>();
+
+            let secret_key = any::<SmallRng>()
+                .prop_map(|mut rng| {
+                    RootSeed::from_rng(&mut rng).derive_node_key_pair(&mut rng)
+                })
+                .prop_map(secp256k1::SecretKey::from);
+            (
+                currency,
+                description,
+                payment_hash,
+                payment_secret,
+                timestamp,
+                min_final_cltv_expiry,
+                secret_key,
+            )
+                .prop_map(
+                    |(
+                        currency,
+                        description,
+                        payment_hash,
+                        payment_secret,
+                        timestamp,
+                        min_final_cltv_expiry,
+                        secret_key,
+                    )| {
+                        let invoice = InvoiceBuilder::new(currency)
+                            .description(description)
+                            .payment_hash(payment_hash)
+                            .payment_secret(payment_secret)
+                            .timestamp(timestamp)
+                            .min_final_cltv_expiry(min_final_cltv_expiry)
+                            .build_signed(|hash| {
+                                Secp256k1::new()
+                                    .sign_ecdsa_recoverable(hash, &secret_key)
+                            })
+                            .expect("Could not build invoice");
+                        Self(invoice)
+                    },
+                )
+                .boxed()
+        }
+    }
+
+    #[test]
+    fn invoice_serde_roundtrip() {
+        roundtrip::serde_roundtrip_proptest::<LxInvoice>();
+    }
+
+    #[test]
+    fn invoice_fromstr_display_roundtrip() {
+        roundtrip::fromstr_display_roundtrip_proptest::<LxInvoice>();
+    }
+}