testing.md

Testing utilities

Helpers that guarantee the environment is restored after each test.

import envie
import envie/testing

pub fn my_feature_test() {
  testing.with_env([#("PORT", "3000"), #("DEBUG", "true")], fn() {
    let port = envie.get_int("PORT", 8080)
    port |> should.equal(3000)
  })
  // Original environment is restored automatically
}

pub fn isolated_test() {
  testing.isolated(fn() {
    envie.get("PATH") |> should.equal(Error(Nil))
  })
  // Everything restored
}

Warning

Test Concurrency: Environment variables are global to the process. Since Gleam runs tests in parallel by default, multiple tests using testing.* concurrently may interfere with each other. Use gleam test -- --seed 123 (or any seed) to run tests with a single worker if you encounter flaky tests.