A billing-only change broke the checkout scenarios

Problem Description

Two of us work in this repo. Checkout lives under features/checkout/ with its step code in features/checkout/steps/, billing lives under features/billing/ with its step code in features/billing/steps/. We set it up that way so the two of us could work without stepping on each other.

Yesterday billing added a step for the reference field on an invoice. Nothing under features/checkout/ was touched in that commit. The checkout scenarios stopped running anyway - see run-output.txt. Billing's two scenarios pass; checkout's two do not even get as far as failing.

We do not understand how a file under features/billing/steps/ can have any effect on a scenario in features/checkout/. Before we start moving directories around we would like to know what is actually going on.

Output Specification

1. Make the whole suite run again. All four scenarios must execute and pass.
2. The sentences in both feature files stay exactly as they are written today - support signed off on that wording.
3. Explain, in no more than three sentences, why a change under features/billing/ affected scenarios under features/checkout/. Write it for the two engineers above, who currently believe the directories keep the two sets of step code apart.
4. A single run must still cover both areas.
5. State the convention you are adopting to stop the same thing happening the next time either of us adds a broadly worded step, and apply it in the files you deliver.
6. Nothing under src/ changes.

Input Files

Extract the following files before beginning.

=============== FILE: features/checkout/promo.feature =============== Feature: Promo codes at checkout

Scenario: A valid code reduces the total Given a cart worth $40.00 When I enter "WELCOME10" in the promo field Then the total is $36.00

Scenario: An unknown code is refused Given a cart worth $40.00 When I enter "NOTREAL" in the promo field Then the message is "Code not found"

=============== FILE: features/checkout/steps/promo.steps.js =============== const assert = require('node:assert'); const { Given, When, Then } = require('@cucumber/cucumber'); const { applyPromo } = require('../../../src/promo');

Given('a cart worth ${float}', function (total) { this.cart = { total }; });

When('I enter {string} in the promo field', function (code) { this.result = applyPromo(this.cart, code); });

Then('the total is ${float}', function (expected) { assert.strictEqual(this.result.total, expected); });

Then('the message is {string}', function (expected) { assert.strictEqual(this.result.message, expected); });

=============== FILE: features/billing/invoice.feature =============== Feature: Invoice details

Scenario: A purchase order number is stored on the invoice Given an invoice for $40.00 When I enter "PO-4471" in the reference field Then the invoice reference is "PO-4471"

Scenario: A blank reference is refused Given an invoice for $40.00 When I enter "" in the reference field Then the message is "Reference is required"

=============== FILE: features/billing/steps/invoice.steps.js =============== const assert = require('node:assert'); const { Given, When, Then } = require('@cucumber/cucumber'); const { setField } = require('../../../src/invoice');

Given('an invoice for ${float}', function (total) { this.invoice = { total }; });

When(/^I enter "(.)" in the (.) field$/, function (value, field) { this.result = setField(this.invoice, field, value); });

Then('the invoice reference is {string}', function (expected) { assert.strictEqual(this.invoice.reference, expected); });

=============== FILE: src/promo.js =============== const CODES = { WELCOME10: 0.1 };

function applyPromo(cart, code) { const rate = CODES[code]; if (rate === undefined) return { total: cart.total, message: 'Code not found' }; return { total: Number((cart.total * (1 - rate)).toFixed(2)), message: 'Applied' }; }

module.exports = { applyPromo };

=============== FILE: src/invoice.js =============== function setField(invoice, field, value) { if (field !== 'reference') return { message: Unknown field: ${field} }; if (!value) return { message: 'Reference is required' }; invoice.reference = value; return { message: 'Saved' }; }

module.exports = { setField };

=============== FILE: run-output.txt =============== $ npm run bdd

acme-specs@1.0.0 bdd cucumber-js

.A-.A-......

Failures:

1. Scenario: A valid code reduces the total # features/checkout/promo.feature:3 x When I enter "WELCOME10" in the promo field Multiple step definitions match: I enter {string} in the promo field - features/checkout/steps/promo.steps.js:9 /^I enter "(.)" in the (.) field$/ - features/billing/steps/invoice.steps.js:9

2. Scenario: An unknown code is refused # features/checkout/promo.feature:7 x When I enter "NOTREAL" in the promo field Multiple step definitions match: I enter {string} in the promo field - features/checkout/steps/promo.steps.js:9 /^I enter "(.)" in the (.) field$/ - features/billing/steps/invoice.steps.js:9

4 scenarios (2 ambiguous, 2 passed) 12 steps (2 ambiguous, 2 skipped, 8 passed) 0m00.121s

=============== FILE: cucumber.js =============== module.exports = { default: { require: ['features//steps/*.js', 'features/support//*.js'], format: ['progress'], }, };

=============== FILE: package.json =============== { "name": "acme-specs", "version": "1.0.0", "private": true, "scripts": { "bdd": "cucumber-js" }, "devDependencies": { "@cucumber/cucumber": "^10.9.0" } }