From f5c2248a31ef6c75319b665e43530cb2cca6c4c4 Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <me@tobin.cc>
Date: Wed, 11 Dec 2024 13:34:27 +1100
Subject: [PATCH 1/2] units: Derive Default for BlockInterval

A block interval is a relative thing so it makes sense to default to
zero. This is the same as how we derive `Debug` for `relative::Height`
but not `absolute::Height`.
---
 units/src/block.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/units/src/block.rs b/units/src/block.rs
index 6afa29453..bdbf886b0 100644
--- a/units/src/block.rs
+++ b/units/src/block.rs
@@ -93,7 +93,7 @@ impl TryFrom<BlockHeight> for absolute::Height {
 ///
 /// This type is not meant for constructing relative height based timelocks, this is a general
 /// purpose block interval abstraction. For locktimes please see [`locktime::relative::Height`].
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 // Public to try and make it really clear that there are no invariants.
 pub struct BlockInterval(pub u32);

From a4a0f2921cd2425fa46a8ade42f888d5268e6709 Mon Sep 17 00:00:00 2001
From: "Tobin C. Harding" <me@tobin.cc>
Date: Wed, 11 Dec 2024 13:35:34 +1100
Subject: [PATCH 2/2] units: Add regression tests for Default impls

Add a regression test to the `api` tests to check the value returned by
`Default` for all types that implement it.
---
 units/tests/api.rs | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/units/tests/api.rs b/units/tests/api.rs
index eb6a9530e..20746a3a8 100644
--- a/units/tests/api.rs
+++ b/units/tests/api.rs
@@ -98,12 +98,13 @@ struct CommonTraits {
 }
 
 /// A struct that includes all types that implement `Default`.
-#[derive(Default)] // C-COMMON-TRAITS: `Default`
+#[derive(Debug, Default, PartialEq, Eq)] // C-COMMON-TRAITS: `Default`
 struct Default {
     a: Amount,
     b: SignedAmount,
-    c: relative::Height,
-    d: relative::Time,
+    c: BlockInterval,
+    d: relative::Height,
+    e: relative::Time,
 }
 
 /// A struct that includes all public error types.
@@ -249,3 +250,16 @@ fn test_sync() {
     assert_sync::<Types>();
     assert_sync::<Errors>();
 }
+
+#[test]
+fn regression_default() {
+    let got: Default = Default::default();
+    let want = Default {
+        a: Amount::ZERO,
+        b: SignedAmount::ZERO,
+        c: BlockInterval::ZERO,
+        d: relative::Height::ZERO,
+        e: relative::Time::ZERO,
+    };
+    assert_eq!(got, want);
+}