It is difficult to determine the cause of the issue without reproducing it locally. Would you please emulate this problem with a brand new project?
If I downgrade my node version, I resolved.
version 10.1.0 is error.
6.11.2 and 9.4.0 are resolved.
https://www.npmjs.com/package/testcafeIt says "Node.js (version 4 or newer) ". but too new is also bad.
@moffsugita We cannot research the issue without reproducing it locally. So, I suggest you use the Node.js version, which does not have an issue.