In vitest you can expect a Promise to be resolved using this code:

await expect(expected, "custom message").resolves.toBeUndefined()

However, when failing to resolve, the custom message is not shown:

promise rejected "undefined" instead of resolving

How to display this custom message when the expect fails?

In vitest you can expect a Promise to be resolved using this code:

await expect(expected, "custom message").resolves.toBeUndefined()

However, when failing to resolve, the custom message is not shown:

promise rejected "undefined" instead of resolving

How to display this custom message when the expect fails?

• typescript
• promise
• vitest

1 Answer 1

I ended up adding a little util that catches the error and throws the custom message:

export async function expectToResolve(expected: Promise<any>, msg: string) {
  try {
    await expect(expected).resolves.toBeUndefined()
  } catch (cause) {
    throw new Error(msg, {cause})
  }
}

It can be used like this:

await expectToResolve(promise, "custom message");