test: convert Config and Features/Labs to oclif/test 4

[eablack]

This PR is part of a series migrating test files from @oclif/test v2 to v4 following the package upgrade in the foundation PR. This is PR 3 of 11 in the incremental migration plan.

Descripion

Migrates 12 test files in the Configuration and Features/Labs category to be compatible with @oclif/test v4.1.15, including tests for config variable management, feature flags, and labs features. This PR introduces a special case pattern for commands with external dependencies that require the custom runCommand helper.

Files Migrated (12 total)

• test/unit/commands/config/get.unit.test.ts (1 test)
• test/unit/commands/config/index.unit.test.ts (6 tests)
• test/unit/commands/config/set.unit.test.ts (4 tests)
• test/unit/commands/config/unset.unit.test.ts (1 test)
• test/unit/commands/config/edit.unit.test.ts (4 tests) *
• test/unit/commands/features/disable.unit.test.ts (2 tests)
• test/unit/commands/features/enable.unit.test.ts (2 tests)
• test/unit/commands/features/index.unit.test.ts (3 tests)
• test/unit/commands/features/info.unit.test.ts (2 tests)
• test/unit/commands/labs/disable.unit.test.ts (2 tests)
• test/unit/commands/labs/enable.unit.test.ts (2 tests)
• test/unit/commands/labs/index.unit.test.ts (3 tests)

Total: 32 tests migrated ✅

* Special case: Uses custom runCommand helper (see notes below)

Migration Changes

Most tests were updated to use the new @oclif/test v4 API:

Before (v2):

test
  .stdout()
  .nock('https://api.heroku.com', api => api
    .get('/apps/myapp/config-vars')
    .reply(200, {FOO: 'bar'}))
  .command(['config:get', 'FOO', '--app=myapp'])
  .it('gets a config var', ctx => {
    expect(ctx.stdout).to.contain('bar')
  })

After (v4):
it('gets a config var', async () => {
  nock('https://api.heroku.com')
    .get('/apps/myapp/config-vars')
    .reply(200, {FOO: 'bar'})

  const {stdout} = await runCommand(['config:get', 'FOO', '--app=myapp'])

  expect(stdout).to.contain('bar')
})

Key Pattern Changes

- API: Replaced chaining test API with runCommand() function
- Async: Converted callback-style tests to async/await
- Context: Destructured {stdout, stderr, error} from result instead of ctx parameter
- Cleanup: Added afterEach(() => nock.cleanAll()) hooks
- Nock Setup: Moved nock setup inside each test for better isolation

Special Case: config/edit Tests

The config/edit tests required using the custom runCommand helper (from test/helpers/runCommand.ts) instead of @oclif/test's runCommand():

Pattern:
import runCommand from '../../../helpers/runCommand.js'
import {EditorFactory} from '../../../../src/lib/config/util.js'

beforeEach(function () {
  sinon.stub(EditorFactory.prototype, 'createEditor').callsFake(() => ({
    edit: () => Promise.resolve(editedConfig),
  }))
})

it('updates config values', async () => {
  await runCommand(Cmd, ['--app=myapp', 'KEY'])
  expect(updated).to.deep.equal({KEY: 'value'})
})

Why this was necessary:
- The config:edit command depends on the Editor class which spawns vim/VISUAL/EDITOR
- We need to mock the Editor to avoid opening vim during tests
- @oclif/core's internal module loader performs dynamic import() at runtime
- This dynamic import bypasses all ES module mocking attempts (sinon stubs, esmock, etc.)
- The custom helper directly instantiates the command class, allowing sinon stubs to work

This pattern is already used successfully in addons/docs.unit.test.ts for similar reasons (mocking URL opener).

Supporting refactoring:
- Added EditorFactory class in src/lib/config/util.ts with createEditor() method for testability
- Updated src/commands/config/edit.ts to use new EditorFactory().createEditor() instead of direct new Editor()

Testing

✅ All 32 migrated tests pass locally✅ Tests pass in CI✅ No regressions in other test suites✅ Build passes

Test Results:
- Config tests: 15 passing
- Features tests: 9 passing
- Labs tests: 7 passing
- stringToConfig utility: 1 passing

Notes

This PR demonstrates handling of commands with external dependencies that cannot be mocked using standard @oclif/test patterns. The
custom runCommand helper approach provides a reliable solution for these edge cases while maintaining test coverage.

Related

- Part of the @oclif/test v2 → v4 migration plan outlined in OCLIF_TEST_UPGRADE_PR_PLAN.md
- Follows foundation PR: https://github.com/heroku/cli/pull/3447

[k80bowman]

I had a question, but it's not blocking. It looks like maybe you rewrote the test and left these commented out by accident? Otherwise, this looks good!