test: check most possible combination of CNA flags

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

@@ -0,0 +1,79 @@
+import { run, tryNextDev, useTempDir } from '../utils'
+
+describe.each(['app', 'pages'] as const)(
+  'CNA options matrix - %s',
+  (pagesOrApp) => {
+    let nextTgzFilename: string
+
+    beforeAll(() => {
+      if (!process.env.NEXT_TEST_PKG_PATHS) {
+        throw new Error('This test needs to be run with `node run-tests.js`.')
+      }
+
+      const pkgPaths = new Map<string, string>(
+        JSON.parse(process.env.NEXT_TEST_PKG_PATHS)
+      )
+
+      nextTgzFilename = pkgPaths.get('next')!
+    })
+
+    const isApp = pagesOrApp === 'app'
+
+    const allFlagValues = {
+      app: [isApp ? '--app' : '--no-app'],
+      turbo: [process.env.TURBOPACK ? '--turbo' : '--no-turbo'],
+
+      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 { exitCode } = await run(
+          [projectName, ...flags],
+          nextTgzFilename,
+          {
+            cwd,
+          }
+        )
+        expect(exitCode).toBe(0)
+
+        await tryNextDev({
+          cwd,
+          projectName,
+          isApp,
+        })
+      })
+    })
+  }
+)