Fix snapshots for scoped packages

Author: andrewbranch

packages/core/scripts/createSnapshotFixture.js

@@ -15,7 +15,9 @@ if (import.meta.url === "file://" + process.argv[1]) {
  * @param {string} packageSpec 
  */
 async function fetchManifest(packageSpec) {
-  const [packageName, version = "latest"] = packageSpec.split("@");
+  const versionIndex = packageSpec.indexOf("@", 1);
+  const packageName = packageSpec.substring(0, versionIndex < 0 ? undefined : versionIndex);
+  const version = versionIndex < 0 ? "latest" : packageSpec.substring(versionIndex + 1);
   const manifestUrl = `https://registry.npmjs.org/${packageName}/${version}`;
   return fetch(manifestUrl).then((r) => r.json());
 }
@@ -24,7 +26,7 @@ async function fetchManifest(packageSpec) {
  * @param {any} manifest
  */
 async function writePackage(manifest) {
-  const localUrl = new URL(`../test/fixtures/${manifest.name}@${manifest.version}.tgz`, import.meta.url);
+  const localUrl = new URL(`../test/fixtures/${manifest.name.replace("/", "__")}@${manifest.version}.tgz`, import.meta.url);
   const tarballUrl = manifest.dist.tarball;
   const packageBuffer = await fetch(tarballUrl).then((r) => r.arrayBuffer());
   await writeFile(localUrl, Buffer.from(packageBuffer));

packages/core/test/fixtures/@[email protected]

@@ -0,0 +1,30 @@
+# @[email protected]
+
+## Summary
+
+```json
+[
+  {
+    "kind": "FalseCJS",
+    "title": "Types are CJS, but implementation is ESM",
+    "messages": [
+      {
+        "messageText": "Imports of the package under the `node16` module resolution setting when the importing module is ESM (its extension is `.mts` or `.mjs`, or it has a `.ts` or `.js` extension and is in scope of a `package.json` that contains `\"type\": \"module\"`) resolved to CJS types, but ESM implementations.",
+        "messageHtml": "Imports of the package under the <code>node16</code> module resolution setting when the importing module is ESM (its extension is <code>.mts</code> or <code>.mjs</code>, or it has a <code>.ts</code> or <code>.js</code> extension and is in scope of a <code>package.json</code> that contains <code>\"type\": \"module\"</code>) resolved to CJS types, but ESM implementations."
+      }
+    ]
+  }
+]
+```
+
+## Problems
+
+```json
+[
+  {
+    "kind": "FalseCJS",
+    "entrypoint": ".",
+    "resolutionKind": "node16-esm"
+  }
+]
+```