fix: sha256 output was not forcing conversion of u32 words to 4-bytes (…

…#877)

* fix: sha256 output was not forcing conversion of u32 words to 4-bytes

* fix expected gas

crates/evm/src/precompiles/sha256.cairo

@@ -44,7 +44,7 @@ impl Sha256 of Precompile {
         let mut result_bytes = array![];
         for word in result_words_32
             .span() {
-                let word_bytes = (*word).to_be_bytes();
+                let word_bytes = (*word).to_be_bytes_padded();
                 result_bytes.append_span(word_bytes);
             };
 
@@ -96,6 +96,57 @@ mod tests {
         assert_eq!(gas, 72);
     }
 
+    #[test]
+    fn test_sha256_more_than_32_bytes() {
+        let calldata = [
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0xf3,
+            0x45,
+            0x78,
+            0x90,
+            0x7f,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00,
+            0x00
+        ];
+
+        let (gas, result) = Sha256::exec(calldata.span()).unwrap();
+
+        let result: u256 = result.from_be_bytes().unwrap();
+        let expected_result = 0x3b745a1c00d035c334f358d007a430e4cf0ae63aa0556fb05529706de546464d;
+
+        assert_eq!(result, expected_result);
+        assert_eq!(gas, 84); // BASE + 2 WORDS
+    }
+
 
     // source:
     // <https://www.evm.codes/playground?unit=Wei&codeType=Mnemonic&code='wFirsWplaceqparameters%20in%20memorybFFjdata~0vMSTOREvvwDoqcallZSizeZ_1XSizeb1FX_2jaddressY4%200xFFFFFFFFjgasvSTATICCALLvvwPutqresulWalonVonqstackvPOPb20vMLOAD'~Y1j//%20v%5Cnq%20thVj%20wb~0x_Offset~Zb20jretYvPUSHXjargsWt%20Ve%20%01VWXYZ_bjqvw~_>