Testes

Utilizamos o framework Jest, para realizar os nossos testes, você pode ler mais sobre ele aqui
Focamos mais em testar a store, mais especificamente nossas actions e a relação delas com o SDK, mas se tivermos alguma mutation que tem uma lógica mais complexa, testaremos ela também.
Como criar um teste

Continuaremos com o exemplo de Products
// Importamos a store
import { createProductsStore } from "./store";
import { STATUS } from "@/consts";

describe("products store", () => {
  // Nós mockamos o SDK, para podermos simular seu comportamento
  const sdk = {
    products: {
      getProducts: jest.fn(),
      getProduct: jest.fn(),
      createProduct: jest.fn(),
      updateProduct: jest.fn(),
      deleteProduct: jest.fn(),
    },
  };

  // Instanciamos a store e actions
  const { actions } = createProductsStore(sdk);

  // Criamos um produto fake para nós utilizarmos nos testes
  const fakeProduct = {
    name: "product",
    description: "produto bem legal",
    quantity: 100,
    price: 15.9,
  };

  // Ao final de cada teste, é importante resetar as funções que testamos
  afterEach(() => {
    commit.mockReset();
    dispatch.mockReset();
  });

  describe("actions", () => {
    describe("fetchProducts", () => {
      it("should fetch products", async () => {
        sdk.products.products.getProducts.mockImplementation(() => {
          return { success: true, payload: [fakeProducts] };
        });

        await actions.fetchProduts({ commit });
        expect(commit).toCalledWith("setProducts", [fakeProducts]);
      });
    });

    describe("getProduct", () => {
      it("should update form when request has success", async () => {
        sdk.products.getProduct.mockImplementation(() => {
          return { success: true, payload: fakeProduct };
        });
        await actions.getProduct({ commit }, { id: 1 });
        expect(commit).toHaveBeenCalledWith("updateForm", fakeProduct);
        expect(sdk.products.getProduct).toBeCalledWith({ id: 1 });
      });

      it("should not update form when request has not success", async () => {
        sdk.products.getProduct.mockImplementation(() => {
          return { success: false, payload: null };
        });
        await actions.getProduct({ commit }, { id: 1 });
        expect(commit).not.toBeCalled();
      });
    });

    describe("saveProduct", () => {
      it("should create a product when it is new", async () => {
        sdk.products.createProduct.mockImplementation(() => {
          return { success: true, payload: fakeProduct };
        });
        const state = {
          isNew: true,
          product: { ...fakeProduct, id: null },
        };
        await actions.saveProduct({ commit, state });
        expect(commit).toBeCalledWith("updateForm", fakeProduct);
        expect(sdk.products.postProduct).toBeCalledWith({
          ...fakeProduct,
          id: null,
        });
      });

      it("should update a product when it is not new", async () => {
        sdk.products.updateProduct.mockImplementation(() => {
          return { success: true, payload: fakeProduct };
        });
        const state = {
          isNew: false,
          product: fakeProduct,
        };
        await actions.saveProduct({ commit, state });
        expect(commit).toBeCalledWith("updateForm", fakeProduct);
        expect(sdk.products.updateProduct).toBeCalledWith(fakeProduct);
      });
    });
    describe("deleteProduct", () => {
      it("should delete a product", async () => {
        await actions.deleteProduct({ commit }, { id: 1 });
        expect(sdk.products.deleteProduct).toBeCalled();
      });
    });
  });
});