feat!: read .env.test and allow overriding with nuxt.dotenv options

examples/app-vitest-full/.env.test

@@ -0,0 +1 @@
+NUXT_PUBLIC_TEST_VALUE=123

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

@@ -29,6 +29,7 @@ export default defineNuxtConfig({
   runtimeConfig: {
     public: {
       hello: 'world',
+      testValue: 'default'
     },
   },
 })

examples/app-vitest-full/tests/nuxt/config.spec.ts

@@ -5,5 +5,6 @@ it('should return the runtimeConfig from nuxt.config', () => {
   expect(config).toBeTypeOf('object')
   expect(config?.public).toEqual({
     hello: 'world',
+    testValue: 123,
   })
 })

package.json

@@ -53,6 +53,7 @@
     "pathe": "^1.1.1",
     "perfect-debounce": "^1.0.0",
     "radix3": "^1.1.0",
+    "scule": "^1.1.1",
     "std-env": "^3.6.0",
     "ufo": "^1.3.2",
     "unenv": "^1.8.0",

src/config.ts

@@ -1,31 +1,43 @@
 import type { Nuxt, NuxtConfig } from '@nuxt/schema'
 import type { InlineConfig as VitestConfig } from 'vitest'
 import { defineConfig } from 'vite'
+import type { DotenvOptions } from 'c12'
 import type { InlineConfig } from 'vite'
 import { defu } from 'defu'
 import { createResolver } from '@nuxt/kit'
 
+import { applyEnv } from './config/utils'
+
 interface GetVitestConfigOptions {
   nuxt: Nuxt
   viteConfig: InlineConfig
 }
 
+interface LoadNuxtOptions {
+  dotenv?: Partial<DotenvOptions>
+  overrides?: Partial<NuxtConfig>
+}
+
 // https://github.com/nuxt/framework/issues/6496
 async function startNuxtAndGetViteConfig(
   rootDir = process.cwd(),
-  overrides?: Partial<NuxtConfig>
+  options: LoadNuxtOptions = {}
 ) {
   const { loadNuxt, buildNuxt } = await import('@nuxt/kit')
   const nuxt = await loadNuxt({
     cwd: rootDir,
     dev: false,
+    dotenv: defu(options.dotenv, {
+      cwd: rootDir,
+      fileName: '.env.test'
+    }),
     overrides: defu(
       {
         ssr: false,
         test: true,
         modules: ['@nuxt/test-utils/module'],
       },
-      overrides
+      options.overrides
     ),
   })
 
@@ -61,14 +73,17 @@ const excludedPlugins = [
 
 export async function getVitestConfigFromNuxt(
   options?: GetVitestConfigOptions,
-  overrides?: NuxtConfig
+  loadNuxtOptions: LoadNuxtOptions = {}
 ): Promise<InlineConfig & { test: VitestConfig }> {
-  const { rootDir = process.cwd(), ..._overrides } = overrides || {}
+  const { rootDir = process.cwd(), ..._overrides } = loadNuxtOptions.overrides || {}
 
   if (!options) {
     options = await startNuxtAndGetViteConfig(rootDir, {
-      test: true,
-      ..._overrides
+      dotenv: loadNuxtOptions.dotenv,
+      overrides: {
+        test: true,
+        ..._overrides
+      }
     })
   }
 
@@ -83,7 +98,7 @@ export async function getVitestConfigFromNuxt(
       test: {
         dir: process.cwd(),
         environmentOptions: {
-          nuxtRuntimeConfig: options.nuxt.options.runtimeConfig,
+          nuxtRuntimeConfig: applyEnv(options.nuxt.options.runtimeConfig, { prefix: 'NUXT_' }),
           nuxtRouteRules: defu(
             {},
             options.nuxt.options.routeRules,
@@ -177,7 +192,10 @@ export function defineVitestConfig(config: InlineConfig & { test?: VitestConfig
 
     return defu(
       config,
-      await getVitestConfigFromNuxt(undefined, structuredClone(overrides)),
+      await getVitestConfigFromNuxt(undefined, {
+        dotenv: config.test?.environmentOptions?.nuxt?.dotenv,
+        overrides: structuredClone(overrides)
+      }),
     )
   })
 }
@@ -191,6 +209,13 @@ declare module 'vitest' {
        * @default {http://localhost:3000}
        */
       url?: string
+      /**
+       * You can define how environment options are read when loading the Nuxt configuration.
+       */
+      dotenv?: Partial<DotenvOptions>
+      /**
+       * Configuration that will override the values in your `nuxt.config` file.
+       */
       overrides?: NuxtConfig
       /**
        * The id of the root div to which the app should be mounted. You should also set `app.rootId` to the same value.

src/config/utils.ts

@@ -0,0 +1,48 @@
+// TODO: export these
+// https://github.com/unjs/nitro/tree/main/src/runtime/utils.env.ts
+
+import destr from 'destr'
+import { snakeCase } from 'scule'
+
+export type EnvOptions = {
+  prefix?: string
+  altPrefix?: string
+}
+
+export function getEnv (key: string, opts: EnvOptions) {
+  const envKey = snakeCase(key).toUpperCase()
+  return destr(
+    process.env[opts.prefix + envKey] ?? process.env[opts.altPrefix + envKey]
+  )
+}
+
+function _isObject (input: unknown) {
+  return typeof input === 'object' && !Array.isArray(input)
+}
+
+export function applyEnv (obj: Record<string, any>, opts: EnvOptions, parentKey = '') {
+  for (const key in obj) {
+    const subKey = parentKey ? `${parentKey}_${key}` : key
+    const envValue = getEnv(subKey, opts)
+    if (_isObject(obj[key])) {
+      // Same as before
+      if (_isObject(envValue)) {
+        obj[key] = { ...obj[key], ...(envValue as object) }
+        applyEnv(obj[key], opts, subKey)
+      }
+      // If envValue is undefined
+      // Then proceed to nested properties
+      else if (envValue === undefined) {
+        applyEnv(obj[key], opts, subKey)
+      }
+      // If envValue is a primitive other than undefined
+      // Then set objValue and ignore the nested properties
+      else {
+        obj[key] = envValue ?? obj[key]
+      }
+    } else {
+      obj[key] = envValue ?? obj[key]
+    }
+  }
+  return obj
+}