test: add deterministic task behaviour tests

eslint.config.mjs

@@ -5,10 +5,17 @@ import nextTs from "eslint-config-next/typescript";
 const eslintConfig = defineConfig([
   ...nextVitals,
   ...nextTs,
+  {
+    files: ["tests/**/*.cjs"],
+    rules: {
+      "@typescript-eslint/no-require-imports": "off",
+    },
+  },
   // Override default ignores of eslint-config-next.
   globalIgnores([
     // Default ignores of eslint-config-next:
     ".next/**",
+    ".test-build/**",
     "out/**",
     "build/**",
     "next-env.d.ts",