Simplify key generation for tests and debugging

Signed-off-by: Alexis Sellier <alexis@radicle.xyz>

radicle-crypto/src/lib.rs

@@ -374,6 +374,23 @@ impl sqlite::Bindable for &PublicKey {
     }
 }
 
+pub mod keypair {
+    use super::*;
+    use std::env;
+
+    /// Generate a new keypair using OS randomness.
+    pub fn generate() -> KeyPair {
+        #[cfg(debug_assertions)]
+        if env::var("RAD_DEBUG").is_ok() {
+            // Generate a test keypair that is always the same.
+            // This is useful for debugging and testing, since the
+            // public key is known in advance.
+            return KeyPair::from_seed(Seed::new([0xff; 32]));
+        }
+        KeyPair::generate()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::PublicKey;

radicle-crypto/src/ssh/keystore.rs

@@ -5,7 +5,7 @@ use std::{fs, io};
 use thiserror::Error;
 use zeroize::Zeroizing;
 
-use crate::{KeyPair, PublicKey, SecretKey, Signature, Signer, SignerError};
+use crate::{keypair, PublicKey, SecretKey, Signature, Signer, SignerError};
 
 /// A secret key passphrase.
 pub type Passphrase = Zeroizing<String>;
@@ -47,7 +47,7 @@ impl Keystore {
     /// The `comment` is associated with the private key.
     /// The `passphrase` is used to encrypt the private key.
     pub fn init(&self, comment: &str, passphrase: &str) -> Result<PublicKey, Error> {
-        let pair = KeyPair::generate();
+        let pair = keypair::generate();
         let ssh_pair = ssh_key::private::Ed25519Keypair::from_bytes(&pair)?;
         let ssh_pair = ssh_key::private::KeypairData::Ed25519(ssh_pair);
         let secret = ssh_key::PrivateKey::new(ssh_pair, comment)?;