import { warnOnce } from 'next/dist/build/output/log' describe('build/output/log', () => { it('warnOnce', () => { const original = console.warn try { const messages = [] console.warn = (m: any) => messages.push(m) warnOnce('test') expect(messages.length).toEqual(1) warnOnce('test again') expect(messages.length).toEqual(2) warnOnce('test', 'more') expect(messages.length).toEqual(3) warnOnce('test') expect(messages.length).toEqual(3) warnOnce('test again') expect(messages.length).toEqual(3) warnOnce('test', 'more') expect(messages.length).toEqual(3) warnOnce('test', 'should', 'add', 'another') expect(messages.length).toEqual(4) } finally { console.warn = original } }) })