Overlooked Use Cases in Your Tasks

The Persistent Problem

Throughout 8 years in software development, I've encountered a persistent problem: poorly specified tasks. Use cases are frequently overlooked by product owners, and critical details only surface during testing — or worse, after users interact with the application.

This changed when I worked with a product owner who used Gherkin for specifications.

The Difference

Gherkin forced shared responsibility. Instead of vague user stories that leave edge cases to the developer's imagination, we had concrete scenarios that both the PO and developer agreed on upfront.

A Practical Example: Coupon Redemption

The vague user story:

"As a user, I should be able to redeem a discount coupon at checkout."

A test based on this might look like:

describe('Coupon Redemption based on User Story', () => {
  it('should allow users to redeem a discount coupon', () => {
    // Mock checkout process
    // Insert coupon code
    expect(finalPrice).toBeDiscounted();
  });
});

One test. One happy path. What about expired coupons? Invalid codes? Already-used coupons?

The Gherkin specification forces you to think:

Scenario: Valid coupon
  Given I have a valid coupon "SAVE20"
  When I apply it at checkout
  Then the price should be reduced by 20%

Scenario: Expired coupon
  Given I have an expired coupon "OLD10"
  When I apply it at checkout
  Then the price should not change
  And I should see "Coupon expired"

The corresponding tests:

describe('Coupon Redemption based on Gherkin', () => {
  it('should apply discount for valid coupon', () => {
    // Mock checkout process
    // Input valid coupon code
    expect(finalPrice).toBeDiscounted();
  });

  it('should show error for expired coupon', () => {
    // Mock checkout process
    // Input expired coupon code
    expect(finalPrice).not.toBeDiscounted();
    expect(displayErrorMessage).toBeCalledWith('Coupon expired');
  });
});

The Takeaway

The tool isn't magic — Gherkin is just a format. What matters is the practice of explicitly defining scenarios before writing code. It surfaces edge cases early, aligns expectations between product and engineering, and results in more comprehensive test coverage.

The best bugs are the ones you find before writing the first line of code.