fix(vitest): stubEnv casts boolean on PROD/SSR/DEV

packages/vitest/src/integrations/vi.ts

@@ -292,7 +292,7 @@ export interface VitestUtils {
    * Changes the value of `import.meta.env` and `process.env`.
    * You can return it back to original value with `vi.unstubAllEnvs`, or by enabling `unstubEnvs` config option.
    */
-  stubEnv: (name: string, value: string) => VitestUtils
+  stubEnv: <T extends string>(name: T, value: T extends 'PROD' | 'DEV' | 'SSR' ? boolean : string) => VitestUtils
 
   /**
    * Reset the value to original value that was available before first `vi.stubGlobal` was called.
@@ -358,6 +358,8 @@ function createVitest(): VitestUtils {
   const _stubsGlobal = new Map<string | symbol | number, PropertyDescriptor | undefined>()
   const _stubsEnv = new Map()
 
+  const _envBooleans = ['PROD', 'DEV', 'SSR']
+
   const getImporter = () => {
     const stackTrace = createSimpleStackTrace({ stackTraceLimit: 4 })
     const importerStack = stackTrace.split('\n')[4]
@@ -550,10 +552,13 @@ function createVitest(): VitestUtils {
       return utils
     },
 
-    stubEnv(name: string, value: string) {
+    stubEnv(name: string, value: string | boolean) {
       if (!_stubsEnv.has(name))
         _stubsEnv.set(name, process.env[name])
-      process.env[name] = value
+      if (_envBooleans.includes(name))
+        process.env[name] = value ? '1' : ''
+      else
+        process.env[name] = String(value)
       return utils
     },
 

test/core/test/stubs.test.ts

@@ -104,4 +104,25 @@ describe('stubbing envs', () => {
     expect(import.meta.env.VITE_TEST_UPDATE_ENV).toBe('development')
     expect(process.env.VITE_TEST_UPDATE_ENV).toBe('development')
   })
+
+  it.each(['PROD', 'DEV', 'SSR'] as const)('requires boolean for env.%s', (name) => {
+    vi.stubEnv(name as 'PROD', false)
+    expect(import.meta.env[name]).toBe(false)
+    expect(process.env[name]).toBe('')
+
+    vi.stubEnv(name as 'PROD', true)
+    expect(import.meta.env[name]).toBe(true)
+    expect(process.env[name]).toBe('1')
+
+    // @ts-expect-error PROD, DEV, SSR expect a boolean
+    vi.stubEnv(name as 'PROD', 'string')
+    // @ts-expect-error PROD, DEV, SSR expect a boolean
+    vi.stubEnv(name, 'string')
+  })
+
+  it('setting boolean casts the value to string', () => {
+    // @ts-expect-error value should be a string
+    vi.stubEnv('MY_TEST_ENV', true)
+    expect(import.meta.env.MY_TEST_ENV).toBe('true')
+  })
 })