Add documentation for helper functions and make tests assert instead of print

Author: NlightNFotis

src/libcprover-rust/src/lib.rs

@@ -23,14 +23,25 @@ pub mod ffi {
 
     extern "Rust" {
         fn print_response(vec: &CxxVector<CxxString>);
+        fn translate_response_buffer(vec: &CxxVector<CxxString>) -> Vec<String>;
     }
 }
 
-fn print_response(vec: &CxxVector<CxxString>) {
-    let vec: Vec<String> = vec
-        .iter()
+/// This is a utility function, whose job is to translate the responses from the C++
+/// API (which we get in the form of a C++ std::vector<std:string>) into a form that
+/// can be easily consumed by other Rust programs.
+pub fn translate_response_buffer(vec: &CxxVector<CxxString>) -> Vec<String> {
+    vec.iter()
         .map(|s| s.to_string_lossy().into_owned())
-        .collect();
+        .collect()
+}
+
+/// This is a utility function, whose aim is to simplify direct printing of the messages
+/// that we get from CBMC's C++ API. Underneath, it's using translate_response_buffer
+/// to translate the C++ types into Rust types and then prints out the strings contained
+/// in the resultant rust vector.
+pub fn print_response(vec: &CxxVector<CxxString>) {
+    let vec: Vec<String> = translate_response_buffer(vec);
 
     for s in vec {
         println!("{}", s);
@@ -82,10 +93,22 @@ mod tests {
         }
 
         // Validate integrity of passed goto-model.
-        client.validate_goto_model();
+        if let Err(_) = client.validate_goto_model() {
+            eprintln!("Failed to validate goto model from files: {:?}", vect);
+            process::exit(1);
+        }
 
+        // ATTENTION: The following `.clone()` is unneeded - I keep it here in order to
+        // make potential printing of the message buffer easier (because of borrowing).
+        // This is also why a print instruction is commented out (as a guide for someone
+        // else in case they want to inspect the output).
+        let validation_msg = "Validating consistency of goto-model supplied to API session";
         let msgs = ffi::get_messages();
-        print_response(msgs);
+        let msgs_assert = translate_response_buffer(msgs).clone();
+
+        assert!(msgs_assert.contains(&String::from(validation_msg)));
+
+        // print_response(msgs);
     }
 
     #[test]
@@ -102,15 +125,22 @@ mod tests {
         }
 
         // Validate integrity of goto-model
-        client.validate_goto_model();
+        if let Err(_) = client.validate_goto_model() {
+            eprintln!("Failed to validate goto model from files: {:?}", vect);
+            process::exit(1);
+        }
 
         if let Err(_) = client.verify_model() {
             eprintln!("Failed to verify model from files: {:?}", vect);
             process::exit(1);
         }
 
+        let verification_msg = "VERIFICATION FAILED";
+
         let msgs = ffi::get_messages();
-        print_response(msgs);
+        let msgs_assert = translate_response_buffer(msgs).clone();
+
+        assert!(msgs_assert.contains(&String::from(verification_msg)));
     }
 
     #[test]
@@ -130,14 +160,20 @@ mod tests {
             eprintln!("Failed to load model from files: {:?}", vect);
             process::exit(1);
         }
+
         // Perform a drop of any unused functions.
         if let Err(err) = client.drop_unused_functions() {
             eprintln!("Error during client call: {:?}", err);
             process::exit(1);
         }
 
-        println!("Just before we print the messages");
+        let instrumentation_msg = "Performing instrumentation pass: dropping unused functions";
+        let instrumentation_msg2 = "Dropping 8 of 11 functions (3 used)";
+
         let msgs = ffi::get_messages();
-        print_response(msgs);
+        let msgs_assert = translate_response_buffer(msgs).clone();
+
+        assert!(msgs_assert.contains(&String::from(instrumentation_msg)));
+        assert!(msgs_assert.contains(&String::from(instrumentation_msg2)));
     }
 }