diff --git a/tests/ffi/build.rs b/tests/ffi/build.rs
index 86f8cd3a5..a1a64b7f0 100644
--- a/tests/ffi/build.rs
+++ b/tests/ffi/build.rs
@@ -15,4 +15,7 @@ fn main() {
         build.define("CXX_TEST_INSTANTIATIONS", None);
     }
     build.compile("cxx-test-suite");
+
+    println!("cargo:rerun-if-changed=tests.cc");
+    println!("cargo:rerun-if-changed=tests.h");
 }