Cache configuration documentation

wasmtime-environ/tests/cache_write_default_config.rs

@@ -1,12 +1,13 @@
 use tempfile;
-use wasmtime_environ::cache_init;
+use wasmtime_environ::cache_create_new_config;
 
 #[test]
 fn test_cache_write_default_config() {
     let dir = tempfile::tempdir().expect("Can't create temporary directory");
     let config_path = dir.path().join("cache-config.toml");
 
-    let errors = cache_init(true, Some(&config_path), true, None);
-    assert!(errors.is_empty());
+    let result = cache_create_new_config(Some(&config_path));
+    assert!(result.is_ok());
     assert!(config_path.exists());
+    assert_eq!(config_path, result.unwrap());
 }