feat(vitest-environment): add support for in-source testing (#651)

Author: danielroe

examples/app-vitest-full/composables/add.ts

@@ -0,0 +1,3 @@
+export const add = (...args: number[]) => {
+  return args.reduce((a, b) => a + b, 0)
+}

examples/app-vitest-full/pages/index.vue

@@ -2,8 +2,16 @@
   <div>Index page</div>
 </template>
 
-<script setup>
+<script lang="ts">
 definePageMeta({
   value: 'set in index',
 })
+if (import.meta.vitest) {
+  const { it, expect } = import.meta.vitest
+  it('add', () => {
+    expect(add()).toBe(0)
+    expect(add(1)).toBe(1)
+    expect(add(1, 2, 3)).toBe(6)
+  })
+}
 </script>

examples/app-vitest-full/vitest.config.ts

@@ -7,6 +7,7 @@ export default defineVitestConfig({
     coverage: {
       reportsDirectory: 'coverage',
     },
+    includeSource: ['../pages/index.vue'],
     environmentOptions: {
       nuxt: {
         rootDir: fileURLToPath(new URL('./', import.meta.url)),

src/module.ts

@@ -45,6 +45,16 @@ export default defineNuxtModule<NuxtVitestOptions>({
       rootStubPath: await resolvePath(resolver.resolve('./runtime/nuxt-root')),
     }))
 
+    // Support for in-source testing
+    if (!nuxt.options.test && !nuxt.options.dev) {
+      nuxt.options.vite.define ||= {}
+      nuxt.options.vite.define['import.meta.vitest'] = 'undefined'
+    }
+
+    nuxt.hook('prepare:types', ({ references }) => {
+      references.push({ types: 'vitest/import-meta' })
+    })
+
     if (!nuxt.options.dev) return
 
     // the nuxt instance is used by a standalone Vitest env, we skip this module