Requirements that can be tested

Play this lesson

"It should feel fast"

A requirement says what the game must do. "It should feel fast" cannot be checked: Kai says it is fast, a tester in Australia says it is slow, and both are right.

A testable requirement names a situation, an action and a result that anyone can check the same way.

Given, When, Then

Gherkin, the format used by the testing tool Cucumber, writes each requirement as a scenario. Given sets the starting situation, When is an action, and Then is the expected result:

Given four players are in one garden
When one player plants a seed
Then all four see it within 300 ms

Quick check

Priya writes the tests. Which requirement can a test check?

  1. Given a player loses connection for 10 seconds, When they reconnect, Then they return to the same garden with their seeds
  2. The game should handle bad internet well
  3. Reconnecting should be smooth
Show the answer

Given a player loses connection for 10 seconds, When they reconnect, Then they return to the same garden with their seeds

It names the situation (10 seconds offline), the action (reconnecting) and a result anyone can check. "Well" and "smooth" mean different things to different people.

Numbers end arguments

Vague words become numbers: "fast" becomes "within 300 ms", "stable" becomes "fewer than 1 crash in 1,000 matches", "fair" becomes "no player gets more than 2 extra seeds per wave".

A number turns an argument into a check that a test or a dashboard can run every day.

Fix the rule

requirements.md
Gardens save often enough.

Which rewrite can a test check?

  1. Given a garden is open, When 30 seconds pass after a change, Then the change is saved on the server
  2. The garden should save a lot
  3. The garden must never lose anything, ever
Show the answer

Given a garden is open, When 30 seconds pass after a change, Then the change is saved on the server

It names a time and a result a test can check, and it matches the studio's decision to save every 30 seconds. "Never, ever" cannot be proven by any test.

Who writes them

The design doc lists the requirements, and the team turns each into scenarios. Remy asks Claude Opus 5.5 to draft Gherkin scenarios from the doc, then reads every line, because a wrong requirement, tested perfectly, is still wrong.

Quick check

A requirement without a number can still be testable, if it names a clear result anyone can check.

Show the answer

True

"Then they return to the same garden with their seeds" has no number, but every tester would agree whether it happened.

The list keeps growing

Once requirements are clear, everyone has ideas for more of them. The last planning skill is the hardest one.

Bolt says: Next: saying no.

Fact-checked 12 October 2026