'use strict'; require('../common'); const assert = require('assert'); process.env.foo = 'foo'; assert.strictEqual(process.env.foo, 'foo'); process.env.foo = undefined; assert.strictEqual(process.env.foo, 'undefined'); process.env.foo = 'foo'; assert.strictEqual(process.env.foo, 'foo'); delete process.env.foo; assert.strictEqual(process.env.foo, undefined);