diff --git a/contrib/test.sh b/contrib/test.sh
index 5047ee429..f4e088e49 100755
--- a/contrib/test.sh
+++ b/contrib/test.sh
@@ -17,6 +17,12 @@ fi
 cargo --version
 rustc --version
 
+# Work out if we are using a nightly toolchain.
+NIGHTLY=false
+if cargo --version | grep nightly; then
+    NIGHTLY=true
+fi
+
 # Test if panic in C code aborts the process (either with a real panic or with SIGILL)
 cargo test -- --ignored --exact 'tests::test_panic_raw_ctx_should_terminate_abnormally' 2>&1 | tee /dev/stderr | grep "SIGILL\\|panicked at '\[libsecp256k1\]"
 
@@ -51,7 +57,7 @@ if [ "$DO_FEATURE_MATRIX" = true ]; then
     RUSTFLAGS='--cfg=fuzzing' RUSTDOCFLAGS=$RUSTFLAGS cargo test --all --features="$FEATURES"
     cargo test --all --features="rand serde"
 
-    if [ "$DO_BENCH" = true ]; then  # proxy for us having a nightly compiler
+    if [ "$NIGHTLY" = true ]; then
         cargo test --all --all-features
         RUSTFLAGS='--cfg=fuzzing' RUSTDOCFLAGS='--cfg=fuzzing' cargo test --all --all-features
     fi
diff --git a/src/key.rs b/src/key.rs
index dfbaa9b71..e38f4aaac 100644
--- a/src/key.rs
+++ b/src/key.rs
@@ -1651,6 +1651,7 @@ mod test {
     use crate::Error::{InvalidPublicKey, InvalidSecretKey};
     use crate::Scalar;
 
+    #[cfg(not(fuzzing))]
     macro_rules! hex {
         ($hex:expr) => ({
             let mut result = vec![0; $hex.len() / 2];