Don't crash if we get 0 data points for small experiments

src/tests.rs

@@ -1685,16 +1685,16 @@ fn print_stats_test_results(
     resp_time: Vec<f64>,
     resp_handle_time: Vec<f64>,
 ) {
-    let mean_req_size = mean(&req_size);
-    let req_std_dev = if &req_size.len() > &1 {standard_deviation(&req_size, Some(mean_req_size))} else {0.0};
-    let mean_req_time = mean(&req_time);
-    let req_time_std_dev = if &req_time.len() > &1 {standard_deviation(&req_time, Some(mean_req_time))} else {0.0};
-    let mean_resp_size = mean(&resp_size);
-    let resp_std_dev = if &resp_size.len() > &1 {standard_deviation(&resp_size, Some(mean_resp_size))} else {0.0};
-    let mean_resp_time = mean(&resp_time);
-    let resp_time_std_dev = if &resp_time.len() > &1 {standard_deviation(&resp_time, Some(mean_resp_time))} else {0.0};
-    let mean_resp_handle_time = mean(&resp_handle_time);
-    let resp_handle_time_std_dev = if &resp_handle_time.len() > &1 {standard_deviation(&resp_handle_time, Some(mean_resp_handle_time))} else {0.0};
+    let mean_req_size = if req_size.len() > 0 {mean(&req_size)} else {0.0};
+    let req_std_dev = if req_size.len() > 1 {standard_deviation(&req_size, Some(mean_req_size))} else {0.0};
+    let mean_req_time = if req_time.len() > 0 {mean(&req_time)} else {0.0};
+    let req_time_std_dev = if req_time.len() > 1 {standard_deviation(&req_time, Some(mean_req_time))} else {0.0};
+    let mean_resp_size = if resp_size.len() > 0 {mean(&resp_size)} else {0.0};
+    let resp_std_dev = if resp_size.len() > 1 {standard_deviation(&resp_size, Some(mean_resp_size))} else {0.0};
+    let mean_resp_time = if resp_time.len() > 0 {mean(&resp_time)} else {0.0};
+    let resp_time_std_dev = if resp_time.len() > 1 {standard_deviation(&resp_time, Some(mean_resp_time))} else {0.0};
+    let mean_resp_handle_time = if resp_handle_time.len() > 0 {mean(&resp_handle_time)} else {0.0};
+    let resp_handle_time_std_dev = if resp_handle_time.len() > 1 {standard_deviation(&resp_handle_time, Some(mean_resp_handle_time))} else {0.0};
 
     println!("Average request size = {} bytes", mean_req_size);
     println!("Request size standard deviation = {} bytes", req_std_dev);