ethcore test::helpers cleanup (#8086)

ethcore/src/client/client.rs

@@ -2205,7 +2205,7 @@ mod tests {
 	#[test]
 	fn should_not_cache_details_before_commit() {
 		use client::{BlockChainClient, ChainInfo};
-		use tests::helpers::*;
+		use tests::helpers::{generate_dummy_client, get_good_dummy_block_hash};
 
 		use std::thread;
 		use std::time::Duration;