Merge #294: Add optional arguments budget and env to run_program test helper

7529af3 Add optional arguments budget and env to run_program test helper (Michael Zaikin)

Pull request description:

  `run_program` test helper is quite useful because it allows to run programs in (almost) the same way they would be run in Elements/Liquid node. The execution behaviour should ideally be identical to `BitMachine`,  but there is a possibility of a divergence and using this helper is a good way to catch it.
  
  This PR adds two optional arguments to allow specifying actual budget and environment. This prevents segmentation fault for some programs.


ACKs for top commit:
  apoelstra:
    ACK 7529af3; successfully ran local tests; thanks!


Tree-SHA512: d7bffcdb65285a5a12d76a9f5c6e7753444f2cb6e5a3d1e365c73c52ad4991cbdac7667d15c16741a0ce7fbebfddc505a687e4d457ca457c9a54ecffb1a8c584

Author: apoelstra

fuzz/fuzz_targets/c_rust_merkle.rs

@@ -27,7 +27,7 @@ fn do_test(data: &[u8]) {
     };
 
     let (program, witness) = data.split_at(prog_len);
-    let c_result = run_program(program, witness, TestUpTo::CheckOneOne);
+    let c_result = run_program(program, witness, TestUpTo::CheckOneOne, None, None);
 
     let prog_iter = BitIter::from(program);
     let wit_iter = BitIter::from(witness);

simplicity-sys/src/tests/mod.rs

@@ -16,6 +16,7 @@ use crate::tests::ffi::{
     type_inference::simplicity_mallocTypeInference,
     SimplicityErr,
 };
+use crate::CElementsTxEnv;
 
 /// The result of parsing, typechecking, and running a Simplicity program
 /// through the C FFI
@@ -72,7 +73,8 @@ pub fn run_test(
     target_ihr: &[u32; 8],
     cost_bound: ubounded,
 ) {
-    let result = run_program(program, witness, TestUpTo::Everything).expect("running program");
+    let result =
+        run_program(program, witness, TestUpTo::Everything, None, None).expect("running program");
     assert_eq!(result.amr, CSha256Midstate { s: *target_amr });
     assert_eq!(result.cmr, CSha256Midstate { s: *target_cmr });
     assert_eq!(result.ihr, CSha256Midstate { s: *target_ihr });
@@ -90,7 +92,8 @@ pub fn run_test_fail(
     target_ihr: &[u32; 8],
     cost_bound: ubounded,
 ) {
-    let result = run_program(program, witness, TestUpTo::Everything).expect("running program");
+    let result =
+        run_program(program, witness, TestUpTo::Everything, None, None).expect("running program");
     assert_eq!(result.amr, CSha256Midstate { s: *target_amr });
     assert_eq!(result.cmr, CSha256Midstate { s: *target_cmr });
     assert_eq!(result.ihr, CSha256Midstate { s: *target_ihr });
@@ -110,10 +113,13 @@ impl Drop for FreeOnDrop {
 /// Run a program and return data about it
 ///
 /// This is mostly a direct port of `run_program` in C `tests.c`.
+/// WARNING: empty environment could lead to a crash (depending on which jets are used).
 pub fn run_program(
     program: &[u8],
     witness: &[u8],
     test_up_to: TestUpTo,
+    budget: Option<u32>,
+    env: Option<&CElementsTxEnv>,
 ) -> Result<TestOutput, SimplicityErr> {
     let mut result = TestOutput {
         amr: CSha256Midstate::default(),
@@ -266,8 +272,9 @@ pub fn run_program(
         }
 
         // 9. Run the program
-        result.eval_result =
-            simplicity_evalTCOProgram(dag, type_dag, len, ptr::null(), ptr::null());
+        let budget_ptr = budget.map(|b| b as *const _).unwrap_or(ptr::null());
+        let env_ptr = env.map(|e| e as *const _).unwrap_or(ptr::null());
+        result.eval_result = simplicity_evalTCOProgram(dag, type_dag, len, budget_ptr, env_ptr);
     }
 
     Ok(result)

src/node/mod.rs

@@ -723,8 +723,14 @@ mod tests {
     fn check_merkle_roots(test: &TestData) {
         let prog = BitIter::from(test.prog.as_slice());
         let witness = BitIter::from(test.witness.as_slice());
-        ffi::tests::run_program(&test.prog, &test.witness, ffi::tests::TestUpTo::CheckOneOne)
-            .unwrap();
+        ffi::tests::run_program(
+            &test.prog,
+            &test.witness,
+            ffi::tests::TestUpTo::CheckOneOne,
+            None,
+            None,
+        )
+        .unwrap();
         let prog = RedeemNode::<Elements>::decode(prog, witness).unwrap();
         assert_eq!(prog.cmr().to_byte_array(), test.cmr);
         assert_eq!(prog.amr().to_byte_array(), test.amr);