Working as a software developer, I've encountered many approaches to distilling desired behaviors into many forms. This traditionally has looked like gathering requirements for Users and/or Systems, and encoding those requirements into a large

Gherkin

Feature: Some terse yet descriptive text of what is desired
  Textual description of the business value of this feature
  Business rules that govern the scope of the feature
  Any additional information that will make the feature easier to understand

  Scenario: Some determinable business situation
    Given some precondition
      And some other precondition
    When some action by the actor
      And some other action
      And yet another action
        Then some testable outcome is achieved
          And something else we can check happens too

  Scenario: A different situation