Add beforeEach hook to clear test environment variables

src/__tests__/filesystem/dev-env/dev-env.test.ts

@@ -1,7 +1,10 @@
-import { describe, expect, test } from "vitest"
+import { beforeEach, describe, expect, test } from "vitest"
 import { setupEnv } from "../../../index"
+import { clearTestEnvVars } from "../../utils"
 
 describe("Dev Files", () => {
+  beforeEach(clearTestEnvVars)
+
   test("env dev test", () => {
     process.env.NODE_ENV = "DEVELOPMENT"
 
@@ -11,6 +14,16 @@ describe("Dev Files", () => {
     expect(process.env.FROM_EXPAND).toEqual(".env.development.local")
   })
 
+  test("do not override a variable that is present in the process.env", () => {
+    process.env.NODE_ENV = "DEVELOPMENT"
+    process.env.MY_ENV = "process.env"
+
+    setupEnv(__dirname)
+
+    expect(process.env.MY_ENV).toBe("process.env")
+    expect(process.env.FROM_EXPAND).toBe(".env.development.local")
+  })
+
   describe("Custom ENV var", () => {
     test("env dev test", () => {
       process.env.NODE_CONTEXT = "DEVELOPMENT"

src/__tests__/filesystem/test-env/test-env.test.ts

@@ -1,7 +1,10 @@
-import { describe, expect, test } from "vitest"
+import { beforeEach, describe, expect, test } from "vitest"
 import { setupEnv } from "../../../index"
+import { clearTestEnvVars } from "../../utils"
 
 describe("env: TEST", () => {
+  beforeEach(clearTestEnvVars)
+
   test("do not load .local files", () => {
     process.env.NODE_ENV = "TEST"
 

src/__tests__/setupEnv.test.ts

@@ -1,22 +1,14 @@
-import fs from "node:fs"
 import dotEnv from "dotenv"
-import { afterEach, beforeEach, describe, expect, test, vitest } from "vitest"
+import fs from "node:fs"
+import { beforeEach, describe, expect, test, vitest } from "vitest"
 import { setupEnv } from "../index"
+import { clearTestEnvVars } from "./utils"
 
 vitest.mock("node:fs")
 vitest.mock("dotenv")
 
 describe("Env", () => {
-  const env = process.env
-
-  beforeEach(() => {
-    vitest.resetAllMocks()
-    process.env = { ...env }
-  })
-
-  afterEach(() => {
-    process.env = env
-  })
+  beforeEach(clearTestEnvVars)
 
   test('node_env="development"', () => {
     process.env.NODE_ENV = "DEVELOPMENT"

src/__tests__/utils.ts

@@ -0,0 +1,6 @@
+export function clearTestEnvVars() {
+  delete process.env.NODE_ENV
+  delete process.env.NODE_CONTEXT
+  delete process.env.MY_ENV
+  delete process.env.FROM_EXPAND
+}