message: [pdsl_core] Set TestEnv caller to [0x0; 32] upon construction
diff: @@ -100,7 +100,7 @@ impl Default for TestEnvData {
  fn default() -> Self {
  Self{
  storage: HashMap::new(),
  - caller: Vec::new(),
  + caller: vec![0x0; 32],
  input: Vec::new(),
  expected_return: Vec::new(),
  total_reads: Cell::new(0),
  