Fix some clippy lint warnings

src/tests/full_test.rs

@@ -422,7 +422,7 @@ fn generate_parameters<CS: CipherSuite>() -> TestVectorParameters {
         server_registration_state,
         client_login_state,
         server_login_state,
-        session_key: client_login_finish_result.session_key.clone(),
+        session_key: client_login_finish_result.session_key,
         export_key: client_registration_finish_result.export_key.to_vec(),
     }
 }

src/tests/opaque_test_vectors.rs

@@ -285,20 +285,20 @@ fn rfc_to_json(input: &str) -> String {
     let mut json = vec![];
     for line in input.lines() {
         // If line contains colon, then
-        if line.contains(":") {
-            if json.len() > 0 {
+        if line.contains(':') {
+            if !json.is_empty() {
                 // Adding closing quote for previous line, comma, and newline
                 json.push("\",\n".to_string());
             }
 
-            let mut iter = line.split(":");
+            let mut iter = line.split(':');
             let key = iter.next().unwrap().split_whitespace().next().unwrap();
             let val = iter.next().unwrap().split_whitespace().next().unwrap();
 
             json.push(format!("    \"{}\": \"{}", key, val));
         } else {
             let s = line.trim().to_string();
-            if s.len() > 0 {
+            if !s.is_empty() {
                 json.push(s);
             }
         }

src/tests/voprf_test_vectors.rs

@@ -21,7 +21,7 @@ struct VOPRFTestVectorParameters {
 
 // Taken from https://github.com/cfrg/draft-irtf-cfrg-voprf/blob/master/draft-irtf-cfrg-voprf.md
 // in base mode
-static OPRF_RISTRETTO255_SHA512: &'static [&str] = &[
+static OPRF_RISTRETTO255_SHA512: &[&str] = &[
     r#"
     {
         "sksm": "758cbac0e1eb4265d80f6e6489d9a74d788f7ddeda67d7fb3c08b08f44bda30a",