Revert "Migrate from ring to ed25519-dalek, take 2 (#3844)" (#3868)

This reverts commit e9b82bacda.

wallet/src/wallet.rs

@@ -776,9 +776,11 @@ mod tests {
     use clap::{App, Arg, SubCommand};
     use serde_json::Value;
     use solana_client::mock_rpc_client_request::SIGNATURE;
+    use solana_sdk::signature::{gen_keypair_file, read_keypair, read_pkcs8, Keypair, KeypairUtil};
     use solana_sdk::transaction::TransactionError;
+    use std::fs;
     use std::net::{Ipv4Addr, SocketAddr};
-    use std::path::PathBuf;
+    use std::path::{Path, PathBuf};
 
     #[test]
     fn test_wallet_config_drone_addr() {
@@ -1421,4 +1423,28 @@ mod tests {
         config.command = WalletCommand::Deploy("bad/file/location.so".to_string());
         assert!(process_command(&config).is_err());
     }
+
+    fn tmp_file_path(name: &str) -> String {
+        use std::env;
+        let out_dir = env::var("OUT_DIR").unwrap_or_else(|_| "target".to_string());
+        let keypair = Keypair::new();
+
+        format!("{}/tmp/{}-{}", out_dir, name, keypair.pubkey()).to_string()
+    }
+
+    #[test]
+    fn test_wallet_gen_keypair_file() {
+        let outfile = tmp_file_path("test_gen_keypair_file.json");
+        let serialized_keypair = gen_keypair_file(outfile.to_string()).unwrap();
+        let keypair_vec: Vec<u8> = serde_json::from_str(&serialized_keypair).unwrap();
+        assert!(Path::new(&outfile).exists());
+        assert_eq!(keypair_vec, read_pkcs8(&outfile).unwrap());
+        read_keypair(&outfile).unwrap();
+        assert_eq!(
+            read_keypair(&outfile).unwrap().pubkey().as_ref().len(),
+            mem::size_of::<Pubkey>()
+        );
+        fs::remove_file(&outfile).unwrap();
+        assert!(!Path::new(&outfile).exists());
+    }
 }