Static Data - Mapping Names to IDs

The endpoint we are looking at currently is products/{id}, which retrieves a product resource by it's numeric ID in the database. This makes sense for the API, but we'd like our Gherkin to reflect the product itself.

Since we know that in our test environments this resource is static, we can treat it as static test data. We can create a mapping object that maps the product name to it's ID in the database. Let's make a const dictionary to map product names to IDs

// src/controllers/products/product.static.ts

export const ProductIdMap = {
  "iPhone 9": 1
} as const;

tip

as const marks the object as compile time constant. So it's schema is literal, and not cast to a generic type like number.

Without const, when hovering over the map in your editor, its shape would be displayed as

{
    'iPhone 9': number
}

Rather than the literal we want:

{
    'iPhone 9': 1
}

If using multiple environments, like dev, test, etc. we might want to set those values with envalid, however we will lose the constant type literals.

// src/controllers/products/product.static.ts
import { Env } from "../../app/env";
export const ProductIdMap = {
  "iPhone 9": Env.PRODUCT_ID_IPHONE_9
};

// src/app/env.ts
import { cleanEnv, num, str } from "envalid";

export const Env = cleanEnv(process.env, {
  API_URL: str({ default: "http://localhost:3000" }),
  PRODUCT_ID_IPHONE_9: num({ default: 1 })
});

Using the Static Data With Expressions

We can also take advantage of expressions here to automatically our products from gherkin.

Consider the following step:

Given I have a product named "iPhone 9"

We can create a new product:static:name expression to map the product name to it's corresponding ID and automatically extract it from steps. As before we can use the AssertKey to validate the input.

// src/controllers/products/product.params.ts
import { ProductIdMap } from "./product.static";
import { defineParameterType } from "@autometa/runner";

defineParameterType(
  {
    name: "product:static:name",
    regex: /"(.*)"/,
    transformer: (name: string) => {
      AssertKey(ProductIdMap, name, `Product Map name ${name}`);
      return ProductIdMap[name];
    }
  } /* .... */
);

And update our types:

import type { App as A, World as W } from "./src";
import type {
  ProductBuilder,
  Product,
  ProductId
} from "./src/controllers/product";
declare module "@autometa/runner" {
  export interface App extends A {}
  export interface World extends W {}
  export interface Types {
    "builder:product": ProductBuilder;
    "product:property": keyof Product;
    "product:static:name": ProductId;
    "world:property:response": keyof W;
  }
}

Now we can use this expression in our step definition:

// src/controllers/products/product.steps.ts
import { Given } from "@autometa/runner";
import { ProductIdMap } from "./product.static";

Given(
  "I want to view the product {product:static:map}",
  async (id, { world }) => {
    world.viewProductId = id;
  }
);

With all that out of the way we can start to write our gherkin tests

Static Data - Mapping Names to IDs

Using the Static Data With Expressions​

Using the Static Data With Expressions