Merge rust-bitcoin#3612: Remove From and Into test impls and create t…

…est-specific function for converting between Rust primitives and U256

33b9d69 Remove From and Into test impls (Shing Him Ng)

Pull request description:

  Created a new `test-utils` module for these functions since it needs to be visible for tests in the `block` module that were also using the previous `From` and `Into` impls.

  Fixes rust-bitcoin#3160

ACKs for top commit:
  apoelstra:
    ACK 33b9d69; successfully ran local tests
  tcharding:
    ACK 33b9d69

Tree-SHA512: 33f2aff7f0a468f12a8d6cd3fe375563ea5ce2870ef23f483fb9d1eeec146e1f4da66ca9ea17eb05fba7693b995d3aa00a0fd9ff0d1e86a358b6b9d7f0ee9288

bitcoin/src/blockdata/block.rs

@@ -369,6 +369,7 @@ mod tests {
     use super::*;
     use crate::consensus::encode::{deserialize, serialize};
     use crate::{CompactTarget, Network, TestnetVersion};
+    use crate::pow::test_utils::{u128_to_work, u64_to_work};
 
     #[test]
     fn test_coinbase_and_bip34() {
@@ -422,7 +423,7 @@ mod tests {
 
         let prevhash = hex!("4ddccd549d28f385ab457e98d1b11ce80bfea2c5ab93015ade4973e400000000");
         let merkle = hex!("bf4473e53794beae34e64fccc471dace6ae544180816f89591894e0f417a914c");
-        let work = Work::from(0x100010001_u128);
+        let work = u128_to_work(0x100010001_u128);
 
         let decode: Result<Block, _> = deserialize(&some_block);
         let bad_decode: Result<Block, _> = deserialize(&cutoff_block);
@@ -468,7 +469,7 @@ mod tests {
 
         let prevhash = hex!("2aa2f2ca794ccbd40c16e2f3333f6b8b683f9e7179b2c4d74906000000000000");
         let merkle = hex!("10bc26e70a2f672ad420a6153dd0c28b40a6002c55531bfc99bf8994a8e8f67e");
-        let work = Work::from(0x257c3becdacc64_u64);
+        let work = u64_to_work(0x257c3becdacc64_u64);
 
         assert!(decode.is_ok());
         let real_decode = decode.unwrap();

bitcoin/src/pow.rs

@@ -1077,21 +1077,36 @@ impl kani::Arbitrary for U256 {
     }
 }
 
+/// In test code, U256s are a pain to work with, so we just convert Rust primitives in many places
 #[cfg(test)]
-mod tests {
-    use super::*;
+pub mod test_utils {
+    use crate::pow::{Target, Work, U256};
+
+    /// Converts a `u64` to a [`Work`]
+    pub fn u64_to_work(u: u64) -> Work {
+        Work(U256::from(u))
+    }
 
-    impl From<u64> for Target {
-        fn from(x: u64) -> Self { Self(U256::from(x)) }
+    /// Converts a `u128` to a [`Work`]
+    pub fn u128_to_work(u: u128) -> Work {
+        Work(U256::from(u))
     }
 
-    impl From<u32> for Target {
-        fn from(x: u32) -> Self { Self(U256::from(x)) }
+    /// Converts a `u32` to a [`Target`]
+    pub fn u32_to_target(u: u32) -> Target {
+        Target(U256::from(u))
     }
 
-    impl<T: Into<u128>> From<T> for Work {
-        fn from(x: T) -> Self { Self(U256::from(x)) }
+    /// Converts a `u64` to a [`Target`]
+    pub fn u64_to_target(u: u64) -> Target {
+        Target(U256::from(u))
     }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::pow::test_utils::{u128_to_work, u32_to_target, u64_to_target};
 
     impl U256 {
         fn bit_at(&self, index: usize) -> bool {
@@ -1102,9 +1117,7 @@ mod tests {
             let word = if index < 128 { self.1 } else { self.0 };
             (word & (1 << (index % 128))) != 0
         }
-    }
 
-    impl U256 {
         /// Constructs a new U256 from a big-endian array of u64's
         fn from_array(a: [u64; 4]) -> Self {
             let mut ret = U256::ZERO;
@@ -1865,7 +1878,7 @@ mod tests {
         ];
 
         for (n_bits, target) in tests {
-            let want = Target::from(target);
+            let want = u64_to_target(target);
             let got = Target::from_compact(CompactTarget::from_consensus(n_bits));
             assert_eq!(got, want);
         }
@@ -1926,7 +1939,7 @@ mod tests {
 
     #[test]
     fn roundtrip_target_work() {
-        let target = Target::from(0xdeadbeef_u32);
+        let target = u32_to_target(0xdeadbeef_u32);
         let work = target.to_work();
         let back = work.to_target();
         assert_eq!(back, target)
@@ -1947,7 +1960,7 @@ mod tests {
 
         for &(chainwork, core_log2) in tests {
             // Core log2 in the logs is rounded to 6 decimal places.
-            let log2 = (Work::from(chainwork).log2() * 1e6).round() / 1e6;
+            let log2 = (u128_to_work(chainwork).log2() * 1e6).round() / 1e6;
             assert_eq!(log2, core_log2)
         }