How to write Gherkin steps with ReScript ? ideas needed (vitest-bdd)

Hi everyone !

In my ongoing quest to support Behavior Driven Development at my company, I created a plugin “vitest-bdd” and I would like to support ReScript as well but do not really know how to solve some issues.

My goal with this plugin is to make it very easy for QA and devs to work together (and write tests that run in parallel with async if needed).

// TypeScript code to configure the Gherkin steps
import { expect } from "vitest";
import { Given } from "vitest-bdd";
import { makeCalculator } from "../../feature/calculator";

Given("I have a {string} calculator", ({ When, Then, And }, name: string) => {
  const calculator = makeCalculator(name);

  When("I add {number} and {number}", calculator.add);
  When("I subtract {number} and {number}", calculator.subtract);
  When("I multiply {number} and {number}", calculator.multiply);
  When("I divide {number} by {number}", calculator.divide);

  Then("the result is {number}", (n: number) => {
    expect(calculator.result.value).toBe(n);
  });
  And("the title is {string}", (s: string) => {
    expect(calculator.title).toBe(s);
  });
});

How should this be done with ReScript ?

There is a lot of weird stuff here…

• the capital letters for functions (can this be solved with t.Given(“…”) ?)
• these files are usually parsed by plugins for cucumber to figure out steps and help write tests with auto-completion
• there is a proxy to support different languages in the { When, Then, …} object to the types resolving to ‘any’ for the arguments, …). Which makes it possible to write { Quand } and then Quand(“je clique sur {string}”, …).

PS: Gherkin test

Feature: Calculator

  Background:
    Given I have a "basic" calculator
    Then the title is "basic"

  Scenario: Add two numbers
    When I add 1 and 2
    Then the result is 3

  Scenario: Divide one number by another
    When I divide 1 by 2
    Then the result is 0.5