chore: import upstream snapshot with attribution

tests/unit/build/optional-transformers-dependency.test.ts

@@ -0,0 +1,45 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+
+const repoRoot = process.cwd();
+
+function readJson<T = Record<string, unknown>>(relPath: string): T {
+  return JSON.parse(readFileSync(join(repoRoot, relPath), "utf8")) as T;
+}
+
+test("@huggingface/transformers is optional so onnxruntime CUDA install failures cannot abort OmniRoute install", () => {
+  const pkg = readJson<{
+    dependencies?: Record<string, string>;
+    optionalDependencies?: Record<string, string>;
+  }>("package.json");
+
+  assert.equal(
+    pkg.dependencies?.["@huggingface/transformers"],
+    undefined,
+    "transformers must not be a regular dependency because it pulls onnxruntime-node install scripts"
+  );
+  assert.equal(pkg.optionalDependencies?.["@huggingface/transformers"], "3.5.2");
+});
+
+test("package-lock marks transformers and its onnxruntime runtime as optional", () => {
+  const lock = readJson<{
+    packages: Record<string, { optional?: boolean; dependencies?: Record<string, string>; optionalDependencies?: Record<string, string> }>;
+  }>("package-lock.json");
+
+  assert.equal(
+    lock.packages[""]?.dependencies?.["@huggingface/transformers"],
+    undefined,
+    "root lock dependencies must not keep transformers as mandatory"
+  );
+  assert.equal(lock.packages[""]?.optionalDependencies?.["@huggingface/transformers"], "3.5.2");
+
+  for (const packagePath of [
+    "node_modules/@huggingface/transformers",
+    "node_modules/onnxruntime-node",
+    "node_modules/onnxruntime-common",
+  ]) {
+    assert.equal(lock.packages[packagePath]?.optional, true, `${packagePath} should be optional`);
+  }
+});