Function makeInnerError

test/specs/singleton.spec.js:80–85

()

    it("can be called with just an inner error", () => {
      function makeInnerError () {
        let innerError = new SyntaxError("This is the inner error");
        innerError.foo = "bar";
        innerError.code = 404;
        return innerError;
      }

      function newErrorWithInnerError (innerErr) {
        return ono(innerErr);