Fix lint warnings in test code

Various combinations of features trigger lint warnings for unused code,
all warnings are caused by incorrect feature gating.

Correct feature gating to remove Clippy warnings during testing.

Author: tcharding

src/key.rs

@@ -1572,6 +1572,7 @@ mod test {
             0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
         ];
 
+        #[cfg(not(fuzzing))]
         let s = Secp256k1::signing_only();
         let sk = SecretKey::from_slice(&SK_BYTES).expect("sk");
 
@@ -1739,7 +1740,8 @@ mod test {
         assert_eq!(set.len(), COUNT);
     }
 
-    #[cfg_attr(not(fuzzing), test)]
+    #[test]
+    #[cfg(not(fuzzing))]
     fn pubkey_combine() {
         let compressed1 = PublicKey::from_slice(
             &hex!("0241cc121c419921942add6db6482fb36243faf83317c866d2a28d8c6d7089f7ba"),
@@ -1759,7 +1761,8 @@ mod test {
         assert_eq!(sum1.unwrap(), exp_sum);
     }
 
-    #[cfg_attr(not(fuzzing), test)]
+    #[test]
+    #[cfg(not(fuzzing))]
     fn pubkey_combine_keys() {
         let compressed1 = PublicKey::from_slice(
             &hex!("0241cc121c419921942add6db6482fb36243faf83317c866d2a28d8c6d7089f7ba"),
@@ -1782,7 +1785,8 @@ mod test {
         assert_eq!(sum1.unwrap(), exp_sum);
     }
 
-    #[cfg_attr(not(fuzzing), test)]
+    #[test]
+    #[cfg(not(fuzzing))]
     fn pubkey_combine_keys_empty_slice() {
         assert!(PublicKey::combine_keys(&[]).is_err());
     }
@@ -1852,6 +1856,7 @@ mod test {
             0218845781f631c48f1c9709e23092067d06837f30aa0cd0544ac887fe91ddd166\
         ";
 
+        #[cfg(not(fuzzing))]
         let s = Secp256k1::new();
         let sk = SecretKey::from_slice(&SK_BYTES).unwrap();
 

src/schnorr.rs

@@ -286,7 +286,7 @@ mod tests {
 
     use super::*;
 
-    #[cfg(any(feature = "alloc", feature = "std"))]
+    #[cfg(all(not(fuzzing), any(feature = "alloc", feature = "std")))]
     macro_rules! hex_32 {
         ($hex:expr) => {{
             let mut result = [0u8; 32];
@@ -458,19 +458,21 @@ mod tests {
     #[test]
     #[cfg(feature = "std")]
     fn test_pubkey_display_output() {
-        let secp = Secp256k1::new();
-        static SK_BYTES: [u8; 32] = [
-            0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
-            0x06, 0x07, 0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x63, 0x63, 0x63, 0x63,
-            0x63, 0x63, 0x63, 0x63,
-        ];
-
-        let kp = KeyPair::from_seckey_slice(&secp, &SK_BYTES).expect("sk");
-
-        // In fuzzing mode secret->public key derivation is different, so
-        // hard-code the epected result.
         #[cfg(not(fuzzing))]
-        let pk = kp.public_key();
+        let pk = {
+            let secp = Secp256k1::new();
+            static SK_BYTES: [u8; 32] = [
+                0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
+                0x06, 0x07, 0xff, 0xff, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x63, 0x63, 0x63, 0x63,
+                0x63, 0x63, 0x63, 0x63,
+            ];
+
+            let kp = KeyPair::from_seckey_slice(&secp, &SK_BYTES).expect("sk");
+
+            // In fuzzing mode secret->public key derivation is different, so
+            // hard-code the epected result.
+            kp.public_key()
+        };
         #[cfg(fuzzing)]
         let pk = XOnlyPublicKey::from_slice(&[0x18, 0x84, 0x57, 0x81, 0xf6, 0x31, 0xc4, 0x8f, 0x1c, 0x97, 0x09, 0xe2, 0x30, 0x92, 0x06, 0x7d, 0x06, 0x83, 0x7f, 0x30, 0xaa, 0x0c, 0xd0, 0x54, 0x4a, 0xc8, 0x87, 0xfe, 0x91, 0xdd, 0xd1, 0x66]).expect("pk");