improve output of C tests

integration-tests/tests/bindings.rs

@@ -1,5 +1,6 @@
 use lazy_static::lazy_static;
 use std::sync::Mutex;
+use tempfile::TempDir;
 
 lazy_static! {
     // the C library running the tests is not reentrant, so we use a mutex to ensure that only one
@@ -11,8 +12,18 @@ macro_rules! suite(
     { $s:ident } => {
     #[test]
     fn $s() {
-        let _guard = MUTEX.lock().unwrap();
-        assert_eq!(integration_tests::bindings_tests::$s(), 0);
+        let tmp_dir = TempDir::new().expect("TempDir failed");
+        let (res, output) = {
+            let _guard = MUTEX.lock().unwrap();
+            // run the tests in the temp dir (NOTE: this must be inside
+            // the mutex guard!)
+            std::env::set_current_dir(tmp_dir.as_ref()).unwrap();
+            integration_tests::bindings_tests::$s()
+        };
+        println!("{}", output);
+        if res != 0 {
+            assert!(false, "test failed");
+        }
     }
     };
 );