Read QuickJS from the built bundle and print the unavailable esbuild fixture skip

vfs/tests/preview1.rs

@@ -231,7 +231,10 @@ async fn poll_preserves_input_and_returns_clock() {
 
 #[tokio::test(flavor = "multi_thread")]
 async fn userland_files() {
-    let qjs = module(&Path::new(env!("CARGO_MANIFEST_DIR")).join("../userland/qjs/qjs.wasm"));
+    let bundle = std::env::var_os("SAUSAGE_USERLAND")
+        .map(std::path::PathBuf::from)
+        .unwrap_or_else(|| Path::new(env!("CARGO_MANIFEST_DIR")).join("../target/userland/bundle"));
+    let qjs = module(&bundle.join("bin/qjs.wasm"));
     let root = Arc::new(Memory::default());
     let script = r#"
         if (os.mkdir('/work') !== 0) throw Error('mkdir');
@@ -282,6 +285,10 @@ async fn userland_files() {
 }
 #[tokio::test(flavor = "multi_thread")]
 async fn esbuild_bundle() {
+    if std::env::var_os("SAUSAGE_NIX_CHECK").is_some() {
+        eprintln!("SKIP preview1::esbuild_bundle: the removed spike fixture requires npm downloads and native Go tooling");
+        return;
+    }
     let dir = tempfile::tempdir().unwrap();
     let fixture = Path::new(env!("CARGO_MANIFEST_DIR")).join("../spikes/s6-esbuild");
     for name in ["app.tsx", "check.mjs", "package.json", "package-lock.json"] {