I have the following solution:

function doubleMessage(number) {
  return `Your number doubled is ${2 * number}`;
}

I need a describe block with Jest to check that the above code block is using template strings. I wrote a helper function outside the describe block to be able to create an expectation like so:

const result = doubleMessage(5);
expect(checkTemplateStringUsage(result)).toBe(true);

I get Expected true to be false as an error.