import { nextTestSetup } from 'e2e-utils' import { check } from 'next-test-utils' describe('custom-app-hmr', () => { const { next } = nextTestSetup({ files: __dirname, }) it('should not do full reload when simply editing _app.js', async () => { const customAppFilePath = 'pages/_app.js' const browser = await next.browser('/') await browser.eval('window.hmrConstantValue = "should-not-change"') const customAppContent = await next.readFile(customAppFilePath) const newCustomAppContent = customAppContent.replace( 'hmr text origin', 'hmr text changed' ) await next.patchFile(customAppFilePath, newCustomAppContent) await check(async () => { const pText = await browser.elementByCss('h1').text() expect(pText).toBe('hmr text changed') // Should keep the value on window, which indicates there's no full reload const hmrConstantValue = await browser.eval('window.hmrConstantValue') expect(hmrConstantValue).toBe('should-not-change') return 'success' }, 'success') await next.patchFile(customAppFilePath, customAppContent) await check(async () => { const pText = await browser.elementByCss('h1').text() expect(pText).toBe('hmr text origin') // Should keep the value on window, which indicates there's no full reload const hmrConstantValue = await browser.eval('window.hmrConstantValue') expect(hmrConstantValue).toBe('should-not-change') return 'success' }, 'success') }) })