federation-testing-tool

Test your Apollo GraphQL Gateway / Federation micro services. With this package you don't have to worry about the whole complexity that comes with joining the GraphQL federated micro services and preparing them for testing.

Install it with

npm install --save-dev federation-testing-tool

Example Usage, for the Federation Demo From Apollo.

Test services in isolation:

const typeDefs = gql`
  extend type Product @key(fields: "upc") {
    upc: String! @external
    weight: Int @external
    price: Int @external
    inStock: Boolean
    shippingEstimate: Int @requires(fields: "price weight")
  }
`;

let inventory = [
  { upc: "1", inStock: true },
  { upc: "2", inStock: false },
  { upc: "3", inStock: true }
];

const resolvers = {
  Product: {
    __resolveReference(object) {
      return {
        ...object,
        ...inventory.find(product => product.upc === object.upc)
      };
    },
    shippingEstimate: object => {
      if (object.price > 1000) return 0;
      return object.weight * 0.5;
    }
  }
};

const service = {
  typeDefs,
  resolvers
};

describe("Based on the data from the external service", () => {
  const query = gql`
    {
      _getProduct {
        inStock
        shippingEstimate
      }
    }
  `;

  it("should set the shippingEstimate at 0 for an expensive item and retrieve inStock", async () => {
    const mocks = {
      Product: () => ({
        upc: "1",
        weight: 10,
        price: 14000,
      })
    };

    const result = await executeGraphql({ query, mocks, service });

    expect(result.data._getProduct.shippingEstimate).toEqual(0);
    expect(result.data._getProduct).toEqual({
      inStock: true,
      shippingEstimate: 0
    });
  });

  it("should calculate the shipping estimate for cheap item", async () => {
    const mocks = {
      Product: () => ({
        upc: "1",
        weight: 10,
        price: 10,
      })
    };

    const result = await executeGraphql({ query, mocks, service });
    expect(result.data._getProduct.shippingEstimate).toEqual(5);
  });
});

Test services together:

const { executeGraphql } = require("federation-testing-tool");
const { gql } = require("apollo-server");

const { typeDefs } = require("./schema");
const { resolvers } = require("./resolvers");

const { typeDefs: typeDefsProducts } = require("../products/schema");

const services = [
  { inventory: { typeDefs, resolvers } },
  {
    products: {
      typeDefs: typeDefsProducts
    }
  }
];

describe("Based on the data from the external service", () => {
  const query = gql`
    {
      topProducts {
        name
        inStock
        shippingEstimate
      }
    }
  `;

  it("should calculate the shipping estimate", async () => {
    const mocks = {
      Product: () => ({
        upc: "1",
        name: "Table",
        weight: 10,
        price: 10,
        elo: "",
        __typename: "Product"
      })
    };

    const result = await executeGraphql({ query, mocks, services });
    expect(result.data.topProducts[0]).toEqual({
      name: "Table",
      inStock: true,
      shippingEstimate: 5
    });
  });
  it("should set the shippingEstimate at 0 for an expensive item", async () => {
    const mocks = {
      Product: () => ({
        upc: "1",
        name: "Table",
        weight: 10,
        price: 14000,
        elo: "",
        __typename: "Product"
      })
    };

    const result = await executeGraphql({ query, mocks, services });
    expect(result.data.topProducts[0]).toEqual({
      name: "Table",
      inStock: true,
      shippingEstimate: 0
    });
  });
});