arrow-express/lib/application/application.spec.ts

Library to bootstrap express applications with zero configuration

import Express from "express";
import { Application } from "./application";
import { vi } from "vitest";
import { Controller, ControllerHandler } from "../controller/controller";
import { Route } from "../route/route";
import { RequestError } from "../error/request.error";
import { ConfigurationError } from "../error/configuration.error";

const ExpressAppStub: Express.Application = {
  use: vi.fn(),
  post: vi.fn(),
  get: vi.fn(),
  _router: {
    stack: [],
  },
} as unknown as Express.Application;

describe("Application", () => {
  afterEach(() => {
    vi.mocked(ExpressAppStub.use).mockReset();
    vi.mocked(ExpressAppStub.post).mockReset();
    vi.mocked(ExpressAppStub.get).mockReset();
  });
  describe("configure", () => {
    it("should throw error if app is configured multiple times", () => {
      const testApplication = Application({ app: ExpressAppStub, logRequests: false });

      testApplication.configure(false);

      expect(testApplication.configure).toThrow();
    });
    describe("route registration", () => {
      it("should register post route", () => {
        const handlerSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(
            Controller().prefix("prefix").registerRoute(Route().method("post").path("path").handler(handlerSpy))
          )
          .configure(false);
        expect(ExpressAppStub.post).toHaveBeenCalledWith("/prefix/path", expect.any(Function));
      });

      it("should register get route", () => {
        const handlerSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(
            Controller().prefix("prefix").registerRoute(Route().method("get").path("").handler(handlerSpy))
          )
          .configure(false);
        expect(ExpressAppStub.get).toHaveBeenCalledWith("/prefix", expect.any(Function));
      });

      it("should register route without path", () => {
        const handlerSpy = vi.fn();
        Application({ app: ExpressAppStub })
          .registerController(Controller().prefix("prefix").registerRoute(Route().method("get").handler(handlerSpy)))
          .configure(false);
        expect(ExpressAppStub.get).toHaveBeenCalledWith("/prefix", expect.any(Function));
      });

      it("should register route with application prefix", () => {
        const handlerSpy = vi.fn();
        Application({ app: ExpressAppStub })
          .prefix("app-prefix")
          .registerController(Controller().prefix("prefix").registerRoute(Route().method("get").handler(handlerSpy)))
          .configure(false);
        expect(ExpressAppStub.get).toHaveBeenCalledWith("/app-prefix/prefix", expect.any(Function));
      });

      it("should register route without path and prefix", () => {
        const handlerSpy = vi.fn();
        Application({ app: ExpressAppStub })
          .registerController(Controller().registerRoute(Route().method("get").handler(handlerSpy)))
          .configure(false);
        expect(ExpressAppStub.get).toHaveBeenCalledWith("/", expect.any(Function));
      });

      it("should throw configuration error when route without method is registered", () => {
        const handlerSpy = vi.fn();
        const app = Application({ app: ExpressAppStub }).registerController(
          Controller().prefix("prefix").registerRoute(Route().path("").handler(handlerSpy))
        );
        expect(() => app.configure(false)).toThrow(ConfigurationError);
      });

      describe("sub controllers", () => {
        it("should register sub controller route", () => {
          const handlerSpy = vi.fn();
          Application({ app: ExpressAppStub })
            .registerController(
              Controller()
                .prefix("root")
                .registerRoute(Route().path("path").method("get").handler(handlerSpy))
                .registerController(Controller().prefix("sub").registerRoute(Route().method("get").handler(handlerSpy)))
            )
            .configure(false);
          expect(ExpressAppStub.get).toHaveBeenCalledWith("/root/sub", expect.any(Function));
          expect(ExpressAppStub.get).toHaveBeenCalledWith("/root/path", expect.any(Function));
        });
      });
    });
  });
  describe("request handling", () => {
    let resSpy: Express.Response;
    beforeEach(() => {
      resSpy = {
        status: vi.fn().mockImplementation(() => resSpy),
        send: vi.fn().mockImplementation(() => resSpy),
        writableEnded: false,
      } as unknown as Express.Response;
    });
    it("should response 200", async () => {
      const spy = vi.fn();
      Application({ app: ExpressAppStub, logRequests: false })
        .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
        .configure(false);
      await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
      expect(resSpy.status).toHaveBeenCalledWith(200);
    });
    it("should not override statusCode", async () => {
      const spy = vi.fn();
      resSpy.statusCode = 301;
      Application({ app: ExpressAppStub, logRequests: false })
        .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
        .configure(false);
      await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
      expect(resSpy.status).not.toHaveBeenCalledWith(200);
    });
    it("should not response 200 when res is not writable", async () => {
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
      (resSpy.writableEnded as boolean) = true;
      const spy = vi.fn();
      Application({ app: ExpressAppStub, logRequests: false })
        .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
        .configure(false);
      await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
      expect(resSpy.status).not.toHaveBeenCalled();
    });

    describe("error handling", () => {
      it("should response code 500 by default", async () => {
        const spy = vi.fn().mockRejectedValue(new RequestError());
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.status).toHaveBeenCalledWith(500);
      });
      it("should response code 500 on non RequestError", async () => {
        const spy = vi.fn().mockRejectedValue(new Error());
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.status).toHaveBeenCalledWith(500);
      });
      it("should response 404", async () => {
        const spy = vi.fn().mockRejectedValue(new RequestError(404));
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.status).toHaveBeenCalledWith(404);
      });
      it("should send error response", async () => {
        const response = {
          code: 1,
          message: "msg",
        };
        const spy = vi.fn().mockRejectedValue(new RequestError(401, response));
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.send).toHaveBeenCalledWith(response);
        expect(resSpy.status).toHaveBeenCalledWith(401);
      });
      it("should not response", async () => {
        // eslint-disable-next-line @typescript-eslint/no-explicit-any
        (resSpy.writableEnded as boolean) = true;
        const spy = vi.fn().mockRejectedValue(new Error());
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().registerRoute(Route().method("get").handler(spy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.status).not.toHaveBeenCalled();
      });
      it("should pass context from controller handler to route handler", async () => {
        const spy = vi.fn().mockResolvedValue("context") as ControllerHandler<any>;
        const routeSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().handler(spy).registerRoute(Route().method("get").handler(routeSpy)))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(routeSpy).toHaveBeenCalledWith(expect.anything(), expect.anything(), "context");
      });

      it("should pass context from root controller to route handler", async () => {
        const spy = vi.fn().mockResolvedValue("context") as ControllerHandler<any>;
        const routeSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(
            Controller()
              .handler(spy)
              .registerController(Controller().registerRoute(Route().method("get").handler(routeSpy)))
          )
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(routeSpy).toHaveBeenCalledWith(expect.anything(), expect.anything(), "context");
      });

      it("should pass context through controllers chain", async () => {
        const rootSpy = vi.fn().mockResolvedValue("root-context") as ControllerHandler<any>;
        const spy = vi
          .fn()
          .mockImplementation((_, __, context) => context + "-child-context") as ControllerHandler<any>;
        const routeSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(
            Controller()
              .handler(rootSpy)
              .registerController(Controller().handler(spy).registerRoute(Route().method("get").handler(routeSpy)))
          )
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(routeSpy).toHaveBeenCalledWith(expect.anything(), expect.anything(), "root-context-child-context");
      });

      it("should pass context through controllers chain if child controllers doesn't have context", async () => {
        const rootSpy = vi.fn().mockResolvedValue("root-context") as ControllerHandler<any>;
        const routeSpy = vi.fn();
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(
            Controller()
              .handler(rootSpy)
              .registerController(Controller().registerRoute(Route().method("get").handler(routeSpy)))
          )
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(routeSpy).toHaveBeenCalledWith(expect.anything(), expect.anything(), "root-context");
      });

      it("should call controller handler", async () => {
        const spy = vi.fn().mockRejectedValue(new Error()) as ControllerHandler<any>;
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().handler(spy).registerRoute(Route().method("get")))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(spy).toHaveBeenCalled();
      });
      it("should send error response from controller handler", async () => {
        const response = {
          code: 1,
          message: "msg",
        };
        const spy = vi.fn().mockRejectedValue(new RequestError(401, response)) as ControllerHandler<any>;
        Application({ app: ExpressAppStub, logRequests: false })
          .registerController(Controller().handler(spy).registerRoute(Route().method("get")))
          .configure(false);
        await vi.mocked(ExpressAppStub.get).mock.calls[0][1]({} as never, resSpy);
        expect(resSpy.send).toHaveBeenCalledWith(response);
        expect(resSpy.status).toHaveBeenCalledWith(401);
      });
    });
  });
});