refactor: update regex test to use OnceLock, refresh binary

Author: vados-cosmonic

tests/regex-test/README.md

@@ -2,7 +2,7 @@ Source code used to create `/wizer/tests/regex_test.wasm`.
 
 Rebuild with:
 
-```
-$ cargo build --release --target wasm32-wasi -p regex-test
-$ cp target/wasm32-wasi/release/regex_test.wasm tests/regex_test.wasm
+```console
+cargo build --release --target wasm32-wasip1 -p regex-test
+cp target/wasm32-wasip1/release/regex_test.wasm tests/regex_test.wasm
 ```

tests/regex-test/src/lib.rs

@@ -1,22 +1,19 @@
 use regex::Regex;
+use std::sync::OnceLock;
 
 /// A regex that matches numbers that start with "1".
-static mut REGEX: Option<Regex> = None;
+static REGEX: OnceLock<Regex> = OnceLock::new();
 
 #[export_name = "wizer.initialize"]
 pub fn init() {
-    unsafe {
-        REGEX = Some(Regex::new(r"^1\d*$").unwrap());
-    }
+    REGEX.get_or_init(|| Regex::new(r"^1\d*$").expect("failed to compile regex"));
 }
 
 #[no_mangle]
 pub fn run(n: i32) -> i32 {
     let s = format!("{}", n);
-    let regex = unsafe { REGEX.as_ref().unwrap() };
-    if regex.is_match(&s) {
-        42
-    } else {
-        0
-    }
+    let regex = REGEX
+        .get()
+        .expect("regex should have been initialized at wizering");
+    if regex.is_match(&s) { 42 } else { 0 }
 }