test: use random SEED numbers

This is needed to omit occurrences of the same seed in a sequence of
following seeds due to the reason of that two initial seed are very
close if based on unix epoch seconds.

Author: ahlinc

cli/src/tests/helpers/mod.rs

@@ -6,7 +6,8 @@ pub(super) mod random;
 pub(super) mod scope_sequence;
 
 use lazy_static::lazy_static;
-use std::{env, time, usize};
+use rand::Rng;
+use std::env;
 
 lazy_static! {
     pub static ref LOG_ENABLED: bool = env::var("TREE_SITTER_LOG").is_ok();
@@ -16,15 +17,18 @@ lazy_static! {
 }
 
 lazy_static! {
-    pub static ref START_SEED: usize =
-        int_env_var("TREE_SITTER_SEED").unwrap_or_else(|| time::SystemTime::now()
-            .duration_since(time::UNIX_EPOCH)
-            .unwrap()
-            .as_secs() as usize,);
+    pub static ref START_SEED: usize = new_seed();
     pub static ref EDIT_COUNT: usize = int_env_var("TREE_SITTER_EDITS").unwrap_or(3);
     pub static ref ITERATION_COUNT: usize = int_env_var("TREE_SITTER_ITERATIONS").unwrap_or(10);
 }
 
 fn int_env_var(name: &'static str) -> Option<usize> {
     env::var(name).ok().and_then(|e| e.parse().ok())
 }
+
+pub(crate) fn new_seed() -> usize {
+    int_env_var("TREE_SITTER_SEED").unwrap_or_else(|| {
+        let mut rng = rand::thread_rng();
+        rng.gen::<usize>()
+    })
+}