test: check most possible combination of CNA flags

test/integration/create-next-app/templates/matrix.test.ts

@@ -0,0 +1,77 @@
+import {
+  createNextApp,
+  spawnExitPromise,
+  tryNextDev,
+  useTempDir,
+} from '../utils'
+
+let testVersion
+beforeAll(async () => {
+  if (testVersion) return
+  // TODO: investigate moving this post publish or create deployed GH#57025
+  // tarballs to avoid these failing while a publish is in progress
+  testVersion = 'latest'
+  // const span = new Span({ name: 'parent' })
+  // testVersion = (
+  //   await createNextInstall({ onlyPackages: true, parentSpan: span })
+  // ).get('next')
+})
+
+describe.each(['app', 'pages'] as const)(
+  'CNA options matrix - %s',
+  (pagesOrApp) => {
+    const allFlagValues = {
+      app: [pagesOrApp === 'app' ? '--app' : '--no-app'],
+      ts: ['--js', '--ts'],
+      importAlias: [
+        '--import-alias=@acme/*',
+        '--import-alias=@/*',
+        '--no-import-alias',
+      ],
+      // doesn't affect if the app builds or not
+      // eslint: ['--eslint', '--no-eslint'],
+      eslint: ['--eslint'],
+      srcDir: ['--src-dir', '--no-src-dir'],
+      tailwind: ['--tailwind', '--no-tailwind'],
+      // shouldn't affect if the app builds or not
+      // packageManager: ['--use-npm', '--use-pnpm', '--use-yarn', '--use-bun'],
+    }
+
+    const getPermutations = <T>(items: T[][]): T[][] => {
+      if (!items.length) return [[]]
+      const [first, ...rest] = items
+      const children = getPermutations(rest)
+      return first.flatMap((value) =>
+        children.map((child) => [value, ...child])
+      )
+    }
+
+    const flagPermutations = getPermutations(Object.values(allFlagValues))
+    const testCases = flagPermutations.map((flags) => ({
+      name: flags.join(' '),
+      flags,
+    }))
+
+    let id = 0
+    it.each(testCases)('$name', async ({ flags }) => {
+      await useTempDir(async (cwd) => {
+        const projectName = `cna-matrix-${pagesOrApp}-${id++}`
+        const childProcess = createNextApp(
+          [projectName, ...flags],
+          {
+            cwd,
+          },
+          testVersion
+        )
+
+        const exitCode = await spawnExitPromise(childProcess)
+        expect(exitCode).toBe(0)
+
+        await tryNextDev({
+          cwd,
+          projectName,
+        })
+      })
+    })
+  }
+)