Initialize WASI context in unit test

Author: kateinoigakukun

packages/npm-packages/ruby-wasm-wasi/tools/run-test-unit.mjs

@@ -36,6 +36,14 @@ const instantiateComponent = async (rootTestFile) => {
   }
   const vm = await RubyVM._instantiate(async (jsRuntime) => {
     const { cli, clocks, filesystem, io, random, sockets } = preview2Shim;
+    const dirname = path.dirname(new URL(import.meta.url).pathname);
+    filesystem._setPreopens({
+      "/__root__": path.join(dirname, ".."),
+      "/usr": path.join(process.env.RUBY_BUILD_ROOT, "usr"),
+      "/bundle": path.join(process.env.RUBY_BUILD_ROOT, "bundle"),
+    })
+    cli._setArgs(["ruby.wasm"].concat(process.argv.slice(2)));
+    cli._setCwd("/")
     const root = await instantiate(getCoreModule, {
       "ruby:js/js-runtime": jsRuntime,
       "wasi:cli/environment": cli.environment,
@@ -59,6 +67,8 @@ const instantiateComponent = async (rootTestFile) => {
       "wasi:sockets/tcp": sockets.tcp,
     })
     return root.rubyRuntime;
+  }, {
+    args: ["ruby.wasm", rootTestFile],
   })
   return { vm };
 }