test(sha256): add NIST test vectors and P2PKH script hash test

  Verify compute_script_hash produces correct SHA-256 output after
  the rust-crypto to sha2 migration. Tests against NIST vectors for
  empty string and abc, plus a real P2PKH scriptPubKey.

Author: EddieHouston

src/new_index/schema.rs

@@ -1975,3 +1975,52 @@ pub mod bench {
         super::add_blocks(&[data.block_entry.clone()], &data.iconfig)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_sha256_empty_input() {
+        // NIST SHA-256 test vector: SHA-256("") = e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
+        let expected: FullHash = [
+            0xe3, 0xb0, 0xc4, 0x42, 0x98, 0xfc, 0x1c, 0x14, 0x9a, 0xfb, 0xf4, 0xc8, 0x99, 0x6f,
+            0xb9, 0x24, 0x27, 0xae, 0x41, 0xe4, 0x64, 0x9b, 0x93, 0x4c, 0xa4, 0x95, 0x99, 0x1b,
+            0x78, 0x52, 0xb8, 0x55,
+        ];
+        let mut hasher = Sha256::new();
+        hasher.update(b"");
+        let result: FullHash = hasher.finalize().into();
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_sha256_abc() {
+        // NIST SHA-256 test vector: SHA-256("abc") = ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad
+        let expected: FullHash = [
+            0xba, 0x78, 0x16, 0xbf, 0x8f, 0x01, 0xcf, 0xea, 0x41, 0x41, 0x40, 0xde, 0x5d, 0xae,
+            0x22, 0x23, 0xb0, 0x03, 0x61, 0xa3, 0x96, 0x17, 0x7a, 0x9c, 0xb4, 0x10, 0xff, 0x61,
+            0xf2, 0x00, 0x15, 0xad,
+        ];
+        let mut hasher = Sha256::new();
+        hasher.update(b"abc");
+        let result: FullHash = hasher.finalize().into();
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn test_p2pkh_script_hash() {
+        // P2PKH scriptPubKey for address 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
+        // OP_DUP OP_HASH160 <20-byte-hash> OP_EQUALVERIFY OP_CHECKSIG
+        let script_hex = "76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac";
+        let script_bytes: Vec<u8> = Vec::from_hex(script_hex).unwrap();
+        let expected: Vec<u8> = Vec::from_hex(
+            "6191c3b590bfcfa0475e877c302da1e323497acf3b42c08d8fa28e364edf018b"
+        ).unwrap();
+
+        let mut hasher = Sha256::new();
+        hasher.update(&script_bytes);
+        let hash: FullHash = hasher.finalize().into();
+        assert_eq!(hash, expected.as_slice());
+    }
+}