Function check

test/compute-engine/latex-syntax/errors.test.ts:7–9

(s: string, f: jest.ProvidesCallback)

engine.declare('g', 'function');

function check(s: string, f: jest.ProvidesCallback) {
  describe(s, () => test(s, f));
}

type ErrorExpressionObject = {
  fn: ['Error', ...MathJsonExpression[]];