test: deduplicate cli option collision fixtures

src/test-utils/secret-file-fixture.ts

@@ -0,0 +1,30 @@
+import fs from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+
+export type SecretFiles = {
+  passwordFile?: string;
+  tokenFile?: string;
+};
+
+export async function withTempSecretFiles<T>(
+  prefix: string,
+  secrets: { password?: string; token?: string },
+  run: (files: SecretFiles) => Promise<T>,
+): Promise<T> {
+  const dir = await fs.mkdtemp(path.join(os.tmpdir(), prefix));
+  try {
+    const files: SecretFiles = {};
+    if (secrets.token !== undefined) {
+      files.tokenFile = path.join(dir, "token.txt");
+      await fs.writeFile(files.tokenFile, secrets.token, "utf8");
+    }
+    if (secrets.password !== undefined) {
+      files.passwordFile = path.join(dir, "password.txt");
+      await fs.writeFile(files.passwordFile, secrets.password, "utf8");
+    }
+    return await run(files);
+  } finally {
+    await fs.rm(dir, { recursive: true, force: true });
+  }
+}