diff --git a/primitives/src/transaction.rs b/primitives/src/transaction.rs
index 7e708e250..05210ee29 100644
--- a/primitives/src/transaction.rs
+++ b/primitives/src/transaction.rs
@@ -645,6 +645,18 @@ impl<'a> Arbitrary<'a> for Txid {
 mod tests {
     use super::*;
 
+    #[test]
+    fn sanity_check() {
+        let version = Version(123);
+        assert_eq!(version.to_u32(), 123);
+        assert_eq!(u32::from(version), 123);
+
+        assert!(!version.is_standard());
+        assert!(Version::ONE.is_standard());
+        assert!(Version::TWO.is_standard());
+        assert!(Version::THREE.is_standard());
+    }
+
     #[test]
     fn transaction_functions() {
         let txin = TxIn {
diff --git a/units/src/amount/tests.rs b/units/src/amount/tests.rs
index d3463660f..e0d506abb 100644
--- a/units/src/amount/tests.rs
+++ b/units/src/amount/tests.rs
@@ -37,6 +37,11 @@ fn sanity_check() {
         assert_eq!(Amount::from_float_in(2_f64, Denomination::Bitcoin).unwrap(), sat(200_000_000));
         assert!(Amount::from_float_in(-100_f64, Denomination::Bitcoin).is_err());
     }
+
+    let result = NumOpResult::Valid(sat(123));
+    assert_eq!(Some(sat(123)), result.ok());
+    assert!(result.is_valid());
+    assert!(!result.is_error());
 }
 
 #[test]
@@ -1010,6 +1015,12 @@ fn sum_amounts() {
     assert_eq!([].iter().sum::<NumOpResult<Amount>>(), Amount::ZERO.into());
     assert_eq!([].iter().sum::<NumOpResult<SignedAmount>>(), SignedAmount::ZERO.into());
 
+    let results = [NumOpResult::Valid(sat(42)), NumOpResult::Valid(sat(1337)), NumOpResult::Valid(sat(21))];
+    assert_eq!(results.iter().sum::<NumOpResult<Amount>>(), NumOpResult::Valid(sat(1400)));
+
+    let signed_results = [NumOpResult::Valid(ssat(42)), NumOpResult::Valid(ssat(1337)), NumOpResult::Valid(ssat(21))];
+    assert_eq!(signed_results.iter().sum::<NumOpResult<SignedAmount>>(), NumOpResult::Valid(ssat(1400)));
+
     let amounts = [sat(42), sat(1337), sat(21)];
     assert_eq!(
         amounts.iter().map(|a| NumOpResult::Valid(*a)).sum::<NumOpResult<Amount>>(),