bug: Fix issue on Vite env not cleaning up after test (testing-library#297)

BREAKING CHANGE: This PR change default behavior for Vitest users. This major should yield no effect to other test frameworks.

Throw error when running vitest with no `afterEach` global and no `VTL_SKIP_AUTO_CLEANUP` flag is set.

Author: Maxim-Mazurok

src/__tests__/auto-cleanup-vitest-globals.js

@@ -0,0 +1,7 @@
+// This test verifies that if test is running from vitest with globals - jest will not throw
+test('works', () => {
+  global.afterEach = () => {} // emulate enabled globals
+  process.env.VITEST = 'true'
+
+  expect(() => require('..')).not.toThrow()
+})

src/__tests__/auto-cleanup-vitest.js

@@ -0,0 +1,10 @@
+// This test verifies that if test is running from vitest without globals - jest will throw
+test('works', () => {
+  delete global.afterEach // no globals in vitest by default
+  process.env.VITEST = 'true'
+
+  expect(() => require('..')).toThrowErrorMatchingInlineSnapshot(`
+    You are using vitest without globals, this way we can't run cleanup after each test.
+    See https://testing-library.com/docs/vue-testing-library/setup for details or set the VTL_SKIP_AUTO_CLEANUP variable to 'true'
+  `)
+})

src/index.js

@@ -8,6 +8,11 @@ if (typeof afterEach === 'function' && !process.env.VTL_SKIP_AUTO_CLEANUP) {
   afterEach(() => {
     cleanup()
   })
+} else if (process.env.VITEST === 'true') {
+  throw new Error(
+    "You are using vitest without globals, this way we can't run cleanup after each test.\n" +
+      "See https://testing-library.com/docs/vue-testing-library/setup for details or set the VTL_SKIP_AUTO_CLEANUP variable to 'true'",
+  )
 }
 
 export * from '@testing-library/dom'